NIECIECKA, Adrianna, KĘDZIORA-KORNATOWSKA, Kornelia, LAMCH, Magdalena, JABŁOŃSKA, Monika, BŁASIK, Natalia and WÓJCIK, Agata. Analysis of the causes of vitamin B12 deficiency in different age groups - a review of the literature. Journal of Education, Health and Sport. Online. 14 December 2022. Vol. 13, no. 2, pp. 81-92. [Accessed 29 June 2025]. DOI 10.12775/JEHS.2023.13.02.011.