6Gill Windlel, Dyfrig Hughes, Pat Linck, Ian Russell, Rhodri Morgan, Bob Woods, Vanessa Burholt, Rhiannon Tudor Edwards, Carla Reeves, Seow Tien Yeo. Public health interventions to promote mental well-being in people aged 65 and over: systematic review of effectiveness and cost-effectiveness[R]. 24 August 2007,1-2.
9Lisa Homsten. Outdoor recreation in Swedish forests-implications for society and forestry[J].Diss-epsilon.slu.se, 2000.
10Li Q. Kobayashi M. Kawada T. Relationships between percentage of forest coverage and standardized mortality ratios (SMR) of cancers in all prefectures in Japan. The Open Public Health Journal 2008,(1): 1-7.