Sun, J., Guo, X., Ma, J., Zhang, J., Jia, C., & Xu, A. (2011). Seasonality of suicide in Shandong China, 1991–2009: Associations with gender, age, area and methods of suicide. Journal of Affective Disorders, 135(1–3), 258–266. http://doi.org/10.1016/j.jad.2011.08.008