1) Urashima, M., Segawa, T., Okazaki, M., Kurihara, M., Wada, Y., Ida, H.(2010, May). Randomized trial of vitamin D supplementation to prevent seasonal influenza A in schoolchildren. Am J Clin Nutr, 91(5):1255-60.
2) https://bio.libretexts.org/Bookshelves/Microbiology/Book%3A_Microbiology_(Boundless)/9%3A_Viruses/9.1%3A_Overview_of_Viruses/9.1A%3A_Discovery_and_Detection_of_Viruses (The LibreTexts libraries are Powered by MindTouch® and are supported by the Department of Education Open Textbook Pilot Project)
