„Metal Contents and Acute Toxicity of Combined Vernonia Amygdalina Leaves and Garcinia Kola Seeds-VAGK, a Herbal and Nutritional Formulation in Male Wistar Rats“. African Journal of Biomedical Research, Bd. 22, Nr. 2, Mai 2019, S. 187-94, https://www.ojshostng.com/index.php/ajbr/article/view/2260.