Shepherd, M., and H. A. Dailey. “Peroxidase Activity of Cytochrome C Facilitates the Protoporphyrinogen Oxidase Reaction”. Cellular and Molecular Biology, vol. 55, no. 1, Feb. 2015, pp. 6-14, https://www.cellmolbiol.org/index.php/CMB/article/view/1066.