1World Health Organization. Mental Health, Facing the Challenges, Building Solutions: Report from the WHO Ministerial Conference. WHO Regional Office for Europe, 2005.
2Juel, K, Sorensen, J, Bronnum-Hansen, H. Risk Factors and Public Health in Denmark [in Danish]. National Institute of Public Health, 2006.
4Eplov, FL, Lauridsen, S. Mental Health Promotion – Background, Concepts and Determinents [in Danish]. The Danish Health Authority, 2008.
5The Danish Health Authority. Long-term Stress – Current Knowledge and Suggestions for Stress Prevention. Advice for General Practice. The Danish Health Authority, 2007.
6Corazon, SS, Stigsdotter, UK, Jensen, AG, Nilsson, K. Development of the nature-based therapy concept for patients with stress-related illness at the Danish healing forest garden Nacadia. J Am Soc Hortic Sci 2010; 20: 34–51.
7Marcus, C, Barnes, M. Healing Garden - Therapeutic Benefits and Design Recommendations (1st edn). Wiley, 1999.
8Detweiler, MB, Sharma, T, Detweiler, JG, Murphy, PF, Lane, S, Carman, J, et al. What is the evidence to support the use of therapeutic gardens for the elderly? Psychiatry Investigat 2012; 9: 100–10.
9Poulsen, VD, Stigsdotter, UK, Refshauge, AD. Whatever happened to the soldiers? Nature-assisted therapies for veterans diagnosed with post-traumatic stress disorder: a literature review. Urban For Urban Green 2015; 14: 438–45.
10Annerstedt, M, Währborg, P. Nature assisted therapy: systematic review of controlled and observational studies. Scand J Publ Health 2011; 39: 371–88.
11Stigsdotter, UK, Palsdottir, AM, Burls, A, Chermaz, A, Ferrini, F, Grahn, P. Nature-based therapeutic interventions. In Forests, Trees and Human Health (eds Nilsson, K and Sangster, M): 309–42. Springer, 2011.
12Butler, AC, Chapman, JE, Forman, EM, Beck, AT. The empirical status of cognitive-behavioral therapy. A review of meta-analyses. Clin Psychol Rev 2006; 26: 17–31.
13Schröder, A, Rehfeld, E, Ørnbøl, E, Sharpe, M, Licht, RW, Fink, P. Cognitive−behavioural group treatment for a range of functional somatic syndromes: randomised trial. Br J Psychiatry 2012; 200: 499–507.
14World Health Organization. The ICD-10 Classification of Mental and Behavioural Disorders: Clinical Descriptions and Diagnostic Guidelines. WHO, 1992.
15Forest & Landscape. Concept Manual for the Therapy Garden Nacadia® [In Danish]. University of Copenhagen, 2008.
16Rehfeld, E, Schröder, A, Fink, P. Specialized Treatment for Severe Bodily Stress. Aarhus University Hospital, 2009.
17Kabat-Zinn, J. Full Catastrophe Living: Using the Wisdom of Your Body and Mind to Face Pain, Stress and Illness. Dell Publishing, 1990.
18Kaplan, R, Kaplan, S. The Experience of Nature (1st edn). Cambridge University Press, 1989.
19Fjorback, LO. Mindfulness Manual. PsykiatriFonden, 2009.
20Antonovsky, A. The salutogentic model as a theory to guide health promotion. Health Promot Int 1996; 11: 11–8.
21Chassany, O, Diderot, D, Dubois, ZD. The Psychological General Well-being Index (PGWBI) User Manual. MAPI Research Institute, 2004.
22Lundgren-Nilsson, A, Jonsdottir, IH, Ahlborg, G, Tennant, A. Construct validity of the psychological general wellbeing index (PGWBI) in a sample of patients undergoing treatment for stress-related exhaustion: a rash analysis. Health Qual. Life Outcomes 2013; 11: 2.
23Lundgren-Nilsson, A, Jonsdottir, IH, Pallant, J, Ahlborg, G. Internal construct validity of the Shirom-Melamed Burnout Questionnaire (SMBQ). BMC Public Health 2012; 11: 2.
24Lindquist, EF. Statistical Analysis in Educational Research. Houghton Mifflin, 1940.
25Alshurafa, M, Briel, M, Akl, EA, Haines, T, Moyyedi, P, Gentles, SJ, et al. Inconsistent definitions for intention-to-treat in relation to missing outcome data: systematic review of the methods literature. PLoS One 2012; 7: e49163.
26Schulz, KD, Altman, DG, Moher, D. The 2010 CONSORT statement: updated guidelines for reporting parallel group randomized trials. BMJ 2010; 340: 698–703.
27Hollis, S, Campbell, F. What is meant by intention to treat analysis? Survey of published randomised controlled trials. BMJ 1999; 319: 670–74.
28Cohen, J. Statistical Power Analysis for the Behavioral Sciences. Routledge Academic, 1988.
29Campbell, M, Fitzpatrick, R, Haines, A, Kinmonth, AL, Sandercock, P, Spiegelhalter, D, et al. Framework for design and evaluation of complex interventions to improve health. Br Med J 2000; 321: 694.
30Berto, R. The role of nature in coping with psycho-physiological stress. A literature review on restorativeness. Behav Sci 2014; 4: 394–409.
31Sidenius, U, Stigsdotter, UK, Poulsen, DV, Bondas, T. ‘I look at my own forest and fields in a different way’: the lived experience of nature-based therapy in a therapy garden when suffering from stress-related illness. Int J Qual Stud Health Well-Being 2017; 12: 1–14.
32Adams, G, Gulliford, MC, Ukoumunne, OC, Eldridge, S, Chinn, S, Campbell, MJ. Patterns of intra-cluster correlation from primary care research to inform study design and analysis. J Clin Epidemiol 2004; 57: 785–94.
33Campbell, MK, Fayers, PM, Grimshaw, M. Determinants of the intracluster correlation coefficient in cluster randomized trials: the case of implementation research. Clin Trials 2005; 2: 99–107.
34Baldwin, S, Murray, DM, Shadish, WR, Pals, SL, Holland, JM, Abramowitz, JS, et al. Intraclass correlation associated with therapists: estimates and applications in planning psychotherapy research. Cogn Behav Ther 2011; 40: 15–31.
35Killip, S, Mahfoud, Z, Pearce, K. What is an intracluster correlation coefficient? Crucial concepts for primary care researchers. Ann Med 2004; 2: 204–8.
36Christie, J, O'Halloran, P, Stevenson, M. Planning a cluster randomized controlled trial: methodological issues. Nurs Res 2009; 58: 128–34.
37Donner, A, Birkett, N, Buck, C. Randomization by cluster: sample size requirements and analysis. Am J Epidemiol 1981; 114: 906–14.