Henshaw, E. B., L. E. Okafor, and H. J. Ekpenyong. “Cutaneous Hyperpigmentation As a Diagnostic Marker of Vitamin B12 Deficiency: A Case Report”. International Journal of Research in Dermatology, vol. 8, no. 3, Apr. 2022, pp. 353-7, doi:10.18203/issn.2455-4529.IntJResDermatol20221015.