1Lenard, P. (1892). Ueber die Electricität der Wasserfälle. Annalen der Physik, 46, 584–636.
2Perez, V., Alexander, D. D., & Bailey, W. H. (2013). Air ions and mood outcomes: A review and meta-analysis. BMC Psychiatry, 13(1), 29.
3Bhattacharya, A., Bhattacharya, S., & Bhattacharya, C. (2012). Effect of negative air ions on cognitive performance. Indian Journal of Positive Psychology, 3(3), 313–319.
4Park, B. J., Tsunetsugu, Y., Kasetani, T., Kagawa, T., & Miyazaki, Y. (2010). The physiological effects of Shinrin-yoku. Environmental Health and Preventive Medicine, 15(1), 18–26.
5Li, Q. (2010). Effect of forest bathing trips on human immune function. Environmental Health and Preventive Medicine, 15(1), 9–17.
6Chevalier, G., Sinatra, S. T., Oschman, J. L., Sokal, K., & Sokal, P. (2012). Earthing: Health implications. Journal of Environmental and Public Health, 2012, 291541.
7Morita, E., Fukuda, S., Nagano, J., Hamajima, N., Yamamoto, H., Iwai, Y., & Shirakawa, T. (2007). Psychological effects of forest environments. Public Health, 121(1), 54–63.