Ho-Pham, L., and M. Nguyen. “Survey on Knowledge and Attitudes on Vitamin D and Sunlight Exposure in an Urban Population in Vietnam”. Journal of the ASEAN Federation of Endocrine Societies, vol. 27, no. 2, May 2014, p. 191, https://www.asean-endocrinejournal.org/index.php/JAFES/article/view/36.