Publications

(excluding published abstracts)

Obtain the fulltexts of most of my publications at Researchgate.

  1. Bohré-den Harder, M., Harinck, F., van der Doef, M.P., van der Toorn, J., & Gebhardt, W.A. (accepted for publication). Current knowledge on organizational humanness and its relation to leadership: a scoping review. Testing, Psychometrics, Methodology in Applied Psychology.
  2. Hendriks, H., Thanh Le, T., Gebhardt, W.A., Van den Putte, B & Vanherle, R. (accepted for publication). Dealing with alcohol-related posts on social media: Using a mixed-method approach to understand young peoples’ problem awareness and evaluations of intervention ideas. International Journal of Environmental Research and Public Health.
  3. Penfornis, K. M., Gebhardt, W. A., Rippe, R. C., Van Laar, C., van den Putte, B., & Meijer, E.(2023). My future-self has (not) quit smoking: An experimental study into the effect of a futureself intervention on smoking-related self-identity constructs. Social Science & Medicine, 115667
  4. Meijer, E., Gebhardt, W.A., van Laar, C., Chavannes, N. H., & van den Putte, B.  (2022). Identified or conflicted: a latent class and regression tree analysis explaining how identity constructs cluster within smokers. BMC Psychology, 10, 231 (2022).
  5. Penfornis, K.M., van Vliet, M. H.M., Meijer, E. & Gebhardt, W.A. (2022). Mapping the evidence on identity processes and identity-related interventions in the smoking and physical activity domains: A scoping review protocol. British Medical Journal Open, 12(7), e058405.
  6. Brust, M., Gebhardt, W. A., van der Voorde, N. A., Numans, M. E., & Kiefte-de Jong, J. C. (2022). The development and validation of scales to measure the presence of a teachable moment following a cardiovascular disease event. Preventive Medicine Reports, 28, 101876.
  7. Vanherle, R., Hendriks, H., Gebhardt, W.A., van den Putte, B. & Beullens, K. (2022). The role of personality factors in young adults’ motives for sharing alcohol references on social networking sites. Cyberpsychology, 16(3).
  8. Kurten, S., Vanherle, R., Beullens, K., Gebhardt, W.A., van den Putte, B., & Hendriks, H. (2022). Like to drink: Dynamics of liking alcohol posts and effects on alcohol use. Computers in Human Behavior, 129, 107145.
  9. Hendriks, H., De Nooij, W., Gebhardt, W.A., Van den Putte, B. (2021). The causal effects of alcohol-related Facebook posts on drinking behavior: Longitudinal experimental study. Journal of Medical Internet Research, 23(11), e28237.
  10. Brust, M., Gebhardt, W.A., Numans, M. E., & Kiefte-de Jong, J. C. (2021). The COVID-19 crisis as a teachable moment for lifestyle change in Dutch cardiovascular disease patients. Frontiers in Psychology, 12.
  11. Nieuwstraten, J.A., van Doorn, L.P., Gebhardt, W.A., & Hamming, J.F. (2021). Stakeholder values and preferences in lower limb amputation for no-option chronic limb threatening ischemia, Patient Preference and Adherence, 15, 1051-1059.
  12. Sandjojo, J., Eltringham, E., Gebhardt, W.A., Zedlitz, A.M.E.E., Embregts, P.J.C.M., & Evers, A.W.M. (2020). Self-management interventions for people with intellectual disabilities: A systematic review. Patient Education and Counseling, 103(10), 1983-1996.
  13. Hendriks, H., Wilmsen, D., Van Dalen, W., & Gebhardt, W.A. (2020). Picture me drinking: Alcohol-related posts by Instagram influencers popular among adolescents and young adults. Frontiers in Psychology, 10, 2991.
  14. Meijer, E., Vangeli, E., Gebhardt, W.A. & van Laar, C. (2020). Identity processes in smokers who want to quit smoking: A longitudinal Interpretative Phenomenological Analysis. Health: An Interdisciplinary Journal for the Social Study of Health, Illness and Medicine, 24(5), 493-517.
  15. Sandjojo, J., Gebhardt, W.A., Zedlitz, A. M. E. E., Hoekman, J., Dusseldorp, E., den Haan, J. A., & Evers, A. W. M. (2019). Development of the Leiden Independence Questionnaire for Support Staff: a measure of staff behaviour regarding promoting independence of people with intellectual disabilities. Journal of Intellectual Disability Research, 63(4), 286-297.
  16. Sandjojo, J.,  Gebhardt, W.A., Zedlitz, A.M.E.E., Hoekman, J., den Haan, J. &  Evers, A.W.M. (2019). Effects of a self-management training for people with intellectual disabilities. Journal of Applied Research in Intellectual Disabilities, 32(2), 390-400.
  17. Sandjojo, J., Hoekman, J., Gebhardt, W.A., Zedlitz, A.M.E.E., den Haan, J. &  Evers, A.W.M. (2019). Promoting independence of people with intellectual disabilities: A focus group study. Perspectives from people with intellectual disabilities, legal representatives, and support staff. Journal of Policy and Practice in Intellectual Disabilities, 16(1), 37-52.
  18. Hendriks, H., van den Putte, B., & Gebhardt, W.A. (2018). Alcoholposts on social networking sites: the Alcoholpost-Typology (APT). Cyberpsychology, Behavior, and Social Networking, 21(7), 463-467.
  19. Hendriks, H., van den Putte, B., Gebhardt, W.A. & Moreno, M. (2018). Social drinking on social media: A content analysis of the social aspects of alcohol-related posts on Facebook and Instagram. Journal of Medical Internet Research, 20(6), e226.
  20. Meijer, E., Gebhardt, W.A., van Laar, C., van den Putte, B. & Evers, A.W.M. (2018). Strengthening quitter self-identity: An experimental study. Psychology and Health, 1-22, 33(10), 1229-1250.
  21. Sandjojo, J., Zedlitz, A.M.E.E., Gebhardt, W.A., Hoekman, J., Dusseldorp, E.M.L., den Haan, J. &  Evers, A.W.M. (2018). Training staff to promote self-management in people with intellectual disabilities. Journal of Applied Research in Intellectual Disabilities, 31, 840–850.
  22. Kunst, L.E. & Gebhardt, W.A. (2018). Prevalence and psychosocial correlates of party-drug use and associated problems among university students in the Netherlands”. Substance Use and Misuse, 53(12), 2077-2088.
  23. Meijer, E., Van den Putte, B., Gebhardt, W.A., Van Laar, C., Bakk, Z., Dijkstra, A., Fong, G. T., West, R. & Willemsen, M. C. (2018). A longitudinal study into the reciprocal effects of identities and smoking behaviour: Findings from the ITC Netherlands Survey. Social Science and Medicine, 200, 249-257.
  24. Cardol, C.K., Escamilla, C.I., Gebhardt, W.A. & Perales, J.C. (2018). Exploring the direct or inverse association of physical activity with behavioral addictions and other self-regulation problems. Addiciones, 926.
  25. Tomee, S.M., Gebhardt, W.A., de Vries, J.P., Hamelinck, V.C., Hamming, J.F. & Lindeman, J.H.N. (2018). Patients’ perceptions of conservative treatment for a small abdominal aortic aneurysm. Patient Preference and Adherence, 12, 119-128.
  26. Claes, N. & Gebhardt, W.A. (2018). Chronic pain and goal conflict/frustration.In Karoly, P., & Crombez, G.(Eds.) Motivational Perspectives on Chronic Pain: Theory, Research and Practice (pp.315-354) Publisher City, State, Oxford University Press.
  27. Hendriks, H., Gebhardt, W.A. & van den Putte, S.J.H.M. (2017). Alcohol-related posts from young people on social networking sites: Content and motivations. Cyberpsychology, Behavior, and Social Networking, 20(7): 428-435.
  28. Meijer, E., van Laar, C., Gebhardt, W.A., Fokkema, M., van den Putte, S.J.H.M., Dijkstra, A., Fong, G., Willemsen, M. (2017). Identity change among smokers and ex-smokers: Findings from the ITC Netherlands Survey. Psychology of Addictive Behaviors, 31(4), 465-478. 
  29. Gebhardt, W.A. (2017). Multiple goal perspective and social identification processes. Addiction, 112(3), 396-398. 
  30. Papamikrouli, E., van Schie, C. M., Schoenmaker, J., Berge, A. B. V., & Gebhardt, W.A. (2017). Peer support needs among adults with burns. Journal of Burn Care & Research, 38(2), 112-120.
  31. Meijer, E., Gebhardt, W.A., Van Laar, C., Kawous, R. & Beijk, S.C. A.M. (2016). Socio-economic status in relation to smoking: The role of (expected and desired) social support and quitter identity. Social Science and Medicine, 162, 41-49.
  32. Groenenberg, I., Crone, M.R., van Dijk, S., Gebhardt, W.A., Ben Meftah, J., Middelkoop, B.J.C., Stiggelbout, A.M., & Assendelft W.J.J. (2015). “‘Check it out!’ Decision-making of vulnerable groups about participation in a two-stage cardiometabolic health check: a qualitative study”. Patient Education and Counseling, 98:234-344.
  33. Huijg, J. M., Gebhardt, W.A., Verheijden, M. W., van der Zouwe, N., de Vries, J. D., Middelkoop, B. J., & Crone, M. R. (2015). Factors influencing primary health care professionals’ physical activity promotion behaviors: a systematic review. International Journal of Behavioral Medicine, 22(1), 32-50.
  34. Huijg, J.M., Dusseldorp, E., Gebhardt, W.A., Verheijden, M.W., van der Zouwe, N., Middelkoop, Duijzer, G. & Crone, M.R. (2015). Factors associated with physical therapists’ implementation of physical activity interventions in the Netherlands. Physical Therapy, 95:539-577.
  35. Kenter, E.J., Gebhardt, W.A., Lottman, I., van Rossum, M., Bekedam, M. & Crone, M.R. (2015). The influence of life events on physical activity patterns of Dutch older adults: A life history method. Psychology & Health, 30:627-651.
  36. Meijer, E., Gebhardt, W.A., Dijkstra, A., Willemsen, M. C., & Van Laar, C. (2015). Quitting smoking: The importance of non-smoker identity in predicting smoking behaviour and responses to a smoking ban. Psychology & Health, 30(12), 1387-1409.
  37. Verkuil, B., Brosschot, J.F., Gebhardt, W.A., & Korrelboom, K. (2015). Goal linking and everyday worries in clinical work stress: a daily diary study. British Journal of Clinical Psychology, 54(4): 378-390.
  38. Huijg, J.M., Gebhardt, W.A., Dusseldorp, E., Verheijden, M. W., Middelkoop, B.J.C., Crone, M.R. (2014). Measuring determinants of implementation behavior: psychometric properties of a questionnaire based on the Theoretical Domains Framework. Implementation Science 9: e33.
  39. Huijg, J.M., Gebhardt, W.A., Crone, M.R., Dusseldorp, E. & Presseau, J. (2014). Discriminant content validity of a Theoretical Domains Framework questionnaire for use in implementation research. Implementation Science, 9:e11.
  40. Rijsdijk, L.E. Bos, A.E.R., Lie, R., Leerlooijer, J.N., Eiling, E., Atema, V., Gebhardt, W.A. & Ruiter, R. (2014). Implementation of school-based comprehensive sex education programmes: A process evaluation of “The World Starts With Me” in Uganda. Health Education Research, 29:340-353.
  41. Segar, M.L. & Gebhardt, W.A. (2014). Pursuing health-related goals. In: M.P. O’Donnell (Ed.). Health Promotion in the Workplace (4th ed).
  42. Casier, A., Goubert, L., Gebhardt, W.A., De Baets, F., Van Aken, S., Matthys, D. & Geert Crombez. (2013). Acceptance and well-being in adolescents with chronic illness: the mediating role of interference and facilitation of life goals by treatment goals. Psychology & Health, 28(11), 1337-1351.
  43. Van der Heiden, S., Gebhardt, W.A., Willemsen, M.C., Nagelhout, G.E., & Dijkstra, A. (2013). Behavioral and psychological responses of lower educated smokers to the smoke-free legislation in Dutch hospitality venues: A qualitative study. Psychology & Health, 28, 49-66.
  44. Huijg, J.M., Crone, M.R., Verheijden, M.W., van der Zouwe, N., Middelkoop, B.J.C., & Gebhardt, W.A. (2013). Factors influencing the adoption, implementation, and continuation of physical activity interventions in PHC: a Delphi study. BMC Family Practice, 14, 142 (9 pages).
  45. Jellema, I.J., Abraham, C., Schaalma, H.P., Gebhardt, W.A. & van Empelen, P. (2013). Predicting having condoms available among adolescents: the role of personal norm and enjoyment. British Journal of Health Psychology, 18(2), 453-468.
  46. Gebhardt, W.A., van der Doef, M.P., Billingy, N. , Carstens, M. & Steenhuis, I. (2012). Preferences for condom placement in stores among young Dutch men and women: relationships with embarrassment and motives for having sex. Sexual Health, 9, 233-239.
  47. Nagelhout, G. E., Willemsen, M. C., Gebhardt, W.A., Van den Putte, B., Hitchman, S. C., Crone, M. R., Fong, G. T., Van der Heiden, S., & De Vries, H. (2012). Does smoke-free legislation and smoking outside bars increase feelings of stigmatization among smokers? Findings from the International Tobacco Control (ITC) Netherlands Survey. Health & Place, 18, 1436-1440.
  48. Massey, E.K., Garnefski, N., Gebhardt, W.A., van der Leeden, R. (2011). A daily diary study on the independent and interactive effects of headache and self-regulatory factors on daily affect among adolescents. British Journal of Health Psychology, 16, 288-299.
  49. Massey, E.K., Gebhardt, W.A., Garnefski, N. (2011). Goals in adolescence. In R.J. Levesque (Ed.). Encyclopedia of Adolescence (pp. 1188-1196). New York, New York: Springer.
  50. Menninga, K.M., Dijkstra, A., Gebhardt, W.A. & Siero, F. (2011). I’m better off now: The role of temporal comparisons and exposure evaluations in smoking cessation. Journal of Health Psychology, 16(7), 1082-1090.
  51. Menninga, K. M., Dijkstra, A., & Gebhardt, W.A. (2011). Mixed feelings: Ambivalence as a predictor of relapse in ex‐smokers. British Journal of Health Psychology, 16(3), 580-591.
  52. Verkuil, B., Brosschot, J.F., Gebhardt, W.A. & Thayer, J.F. (2011). Perseverative cognition, psychopathology and somatic health. In: A.J.J.M. Vingerhoets & I. Nyklicek (Eds.). Emotion regulation and well-being (pp. 85-100). Springer Verlag.
  53. de Vet, E., Gebhardt, W.A., Sinnige, J., de Wit, J.B.F., van Puffelen, A. & van Lettow, B. (2011). Implementation intentions for buying, carrying, discussing and using condoms: the role of quality of plans. Health Education Research, 26(3), 443-455.
  54. Gebhardt, W.A., van der Doef, M.P., Massey, E.K., Verhoeven, CJ.M. & Verkuil, B. (2010). Goal commitment to finding a partner and satisfaction with life among female singles: The mediating role of rumination. Journal of Health Psychology, 15, 122-130.
  55. Menninga, K.M., Dijkstra, A. & Gebhardt, W.A. (2010). Mixed feelings: Ambivalence as a predictor of relapse in ex-smokers. British Journal of Health Psychology, 16, 580-59.
  56. Presseau, J., Sniehotta, F.F., Francis, J.J. & Gebhardt, W.A. (2010). With a little help from my goals: Integrating intergoal facilitation with the theory of planned behaviour to predict physical activity. British Journal of Health Psychology, 15(4), 905-919.
  57. Verkuil, B., Brosschot, J.F., Gebhardt, W.A. & Thayer, J.F. (2010). When worries make you sick: A review of perseverative cognition, the default stress response and somatic health. Journal of Experimental Psychopathology, 1, 87-118.
  58. ter Doest, L.T., Dijkstra, A., Gebhardt, W.A., & Vitale, S. (2009). Cognitions about smoking and not smoking in adolescence. Health Education & Behavior, 36(4), 660-672.
  59. Gebhardt, W.A., van Empelen, P. & van Beurden, D. (2009). Predicting preparatory behaviors for condom use in female undergraduate students: A one-year follow-up study. International Journal of STD & AIDS, 20, 161-164.
  60. Massey, E.K, Gebhardt, W.A. & Garnefski, N. (2009). Self-generated goals and goal process appraisals: Relationships with sociodemographic factors and well-being. Journal of Adolescence, 32, 501-518.
  61. Massey, E.K., Garnefski, N. & Gebhardt, W.A. (2009). Goal frustration, coping and wellbeing in the context of adolescent health: A self-regulation approach. European Journal of Pain, 13, 977-984.
  62. Massey, E.K., Garnefski, N., Gebhardt, W.A., & van der Leeden, R. (2009). Daily frustration, cognitive coping and coping efficacy in adolescent headache: A daily diary study. Headache, 49 (8), 1198-1205.
  63. Gebhardt, W.A. (2008). On multiple goals and continuous conflict. European Health Psychologist, 10(2), 25-28.
  64. Massey, E.K, Gebhardt, W.A. & Garnefski, N. (2008). Adolescent goal content and pursuit: A review of the literature from the past 16 years. Developmental Review, 28, 421-460.
  65. Gebhardt, W.A. (2008). The importance of dynamic goal interaction. In: P.I. Eddington & U.V. Mastolli (Eds.). Health Knowledge, Attitudes, and Practices (pp. 7-10). Hauppauge NY: Nova Science Publishers.
  66. Gebhardt, W.A. (2007). The role of goal facilitation and goal conflict in motivation. In: L.V. Brown (Ed.). Psychology of Motivation (pp.129-140). Hauppauge NY: Nova Science Publishers.
  67. Gebhardt, W.A., Ter Doest, L., Dijkstra, A., Maes, S., Garnefski, N., De Wilde, E.J. & Kraaij, V. (2007). The facilitation of important personal goals through exercise. Perceptual and Motor Skills, 105, 546-548.
  68. ter Doest, L.T., Maes, S., Gebhardt, W.A. & Koelewijn, H. (2006). Personal goal facilitation through work: implications for employee satisfaction and wellbeing. Applied Psychology: An International Review, 55(2), 192-219.
  69. van Empelen, P., Gebhardt, W.A. & Dijkstra, A. (2006). The silent need for a positive self: Why health is not the central human motive in unhealthy and healthy behaviors. Netherlands Journal of Psychology, 62(1), 42-50.
  70. Gebhardt, W.A. (2006). Contextualizing health behaviors: The role of personal goals. In: D. de Ridder & J. de Wit (Eds.). Self-regulation in health behavior. Chichester, UK: John Wiley & Sons.
  71. Gebhardt, W.A., Kuyper, L. & Dusseldorp, E. (2006). Condom use at first intercourse with a new partner in female adolescents and young adults: The role of cognitive planning and motives for having sex. Archives of Sexual Behavior, 35(2), 217-223.
  72. Tromp, D.M., Brouha, X.D.R., Hordijk, G.J., Winnubst, J.A.M., De Leeuw, J.R.J., Gebhardt, W.A. &. van der Doef, M.P. (2005). Medical care-seeking and health-risk behavior in patients with head and neck cancer: The role of health value, control beliefs and psychological distress. Health Education Research, 20(6), 665-675.
  73. Gebhardt, W.A., Kuyper, L., & Greunsven, G. (2003). Need for intimacy in relationships and motives for sex as determinants of adolescent condom use. Journal of Adolescent Health, 33(3), 154-164.
  74. Kraaij, V., Garnefski, N., de Wilde, E.J., Dijkstra, A., Gebhardt, W.A., Maes, S., & ter Doest, L. (2003). Negative life events and depressive symptoms in late adolescence: Bonding and cognitive coping as vulnerability factors? Journal of Youth and Adolescence, 32(3), 185-193.
  75. Gebhardt, W.A. & Brosschot, J.F. (2002). Desirability of control: Psychometric properties and relationships with locus of control, personality, coping, mental and somatic complaints in three Dutch samples. European Journal of Personality, 16(6), 423-438.
  76. Gebhardt, W.A., Kuyper, L., & Greunsven, G. (2002). Meaning of relationships and motives for sex with steady and casual partners. In: I. Real, T. Bothelho, J. Pais Ribeiro (Eds.) Health through the life cycle: A life span perspective (pp.119-123). Lisbon: Instituto Superior de Psicologica Aplicada.
  77. Dijkstra, A., Sweeney, L. & Gebhardt, W.A. (2001). Social cognitive determinants of drinking in young adults: Beyond the alcohol expectancies paradigm. Addictive Behaviors, 26(5), 689-706.
  78. Gebhardt, W.A. & Maes, S. (2001). Integrating social-psychological frameworks for health behavior research. American Journal of Health Behavior, 25(6), 528-536.
  79. Gebhardt, W.A., Doef, M.P. van der & Paul, L. (2001). The revised Dutch Health Hardiness Inventory (RHHI-24): Psychometric properties and relationship with self-reported health behavior and health in two Dutch samples. Health Education Research, 16(5), 579-592.
  80. Maes, S. & Gebhardt, W.A. (2000). Self‑regulation and health behaviour: The health behaviour goal model. In: M. Boekaerts, P.R. Pintrich & M. Zeidner (Eds.). Handbook of self‑regulation. San Diego, CA: Academic Press.
  81. Gebhardt, W.A., Doef, M.P. van der & Maes, S. (1999). Conflicting activities for exercise. Perceptual and Motor Skills, 89(3), 1159-1160.
  82. Gebhardt, W.A., Dusseldorp, E. & Maes, S. (1999). Measuring transitions through stages of exercise behaviour: Application of latent transition analysis. Perceptual and Motor Skills, 88(3), 1097-1106.
  83. Gebhardt, W.A. & Maes, S. (1998). Competing personal goals and exercise behaviour. Perceptual and Motor Skills, 86(3), 755‑759.
  84. Gebhardt, W.A. (1997). Health behaviour goal model: Towards a theoretical framework for health behaviour change. Leiden University: PhD dissertation.
  85. Brosschot, J.F., Gebhardt, W.A. & Godaert, G.L.R. (1994). Internal, powerful others and chance locus of control: Relationships with personality, coping, stress and health. Personality and Individual Differences, 16(6), 839-852.
  86. Gebhardt, W.A. (1994). Effectiveness of training to prevent job-related back pain: A meta-analysis. British Journal of Clinical Psychology, 33(4), 571-574.
  87. Gebhardt, W.A., Sorbi, M.J. & Spierings, E.L.H. (1991). Mood states and the occurrence of migraine attacks. Headache Quarterly, 2(2), 124-129.

In Dutch

  1. Gebhardt, W. & Feijten, P. (2022). Mensbeelden bij beleid: Bewust worden, bespreken en bijstellen. Den Haag: Sociaal en Cultureel Planbureau.
  2. Feijten, P. & Gebhardt, W. (2022). Beleidsmakers moeten zich bewuster worden van hun mensbeelden. Sociale Vraagstukken, 6 december.
  3. Brust, M., Gebhardt, W.A., Numans, M.E. & Kiefte-de Jong, J.C. (2020). Het benutten van teachable moments in de zorg. Nederlands Tijdschrift voor Geneeskunde; 164:D4835
  4. Van der Horst, R.I., Dirksen, C.G., Gebhardt, W.A., Reis, R., Van Steenbergen, J. (2014). Beeldvorming over chronische hepatitis B: Wat weten Turkse virusdragers in Den Haag eigenlijk zelf van hun ziekte? Epidemiologisch Bulletin, 49(1), 11-16.
  5. Gebhardt, W.A. (2012). Leefstijlverandering in de huisarstenpraktijk. Modern Medicine, 6, 211-2013.
  6. Gebhardt, W.A., van Torenburg, S., Vooijs, M., van Rhijn, A. & Tielen, H. (2012). Alcohol & Adolescenten: De achtergronden van alcoholgebruik door jongeren in de gemeente Teylingen: Interviews met 15-jarige jongeren en hun moeders. Universiteit Leiden/Academische Werkplaats Publieke Gezondheid Noordelijk Zuid-Holland.
  7. Gebhardt, W.A. (2011). De veranderbaarheid van leefstijl in de huisartsenpraktijk. In: D.P. Engberts (Ed). Medisch-ethische casuistiek: Leefstijl-autonomie-professionaliteit (p.109-118). Leiden: Boerhaave/LUMC.
  8. Meijer, E., Gebhardt, W.A., van Laar, C., Willemsen, M. & Dijkstra, A. (2013). Het belang van zelfidentiteit en groepsidentiteit als voorspellers van kernreacties op het horecarookverbod. ASPO jaarboek 2013, pp. 137-139.
  9. Kenter, E., Crone, M.R., Gebhardt, W.A., Lottman, I. & Van Rossum, M. (2013). Wat beweegt u? Een kwalitatief onderzoek naar de invloed van levensgebeurtenissen tijdens de ouderdom op het beweeggedrag van senioren uit Alphen aan den Rijn en Oegstgeest. Universiteit Leiden/Academische Werkplaats Publieke Gezondheid Noordelijk Zuid-Holland.