Adeosun, M., S. Edeki, and O. Ugbebor. “On a Variance Gamma Model (VGM) in Option Pricing: A Difference of Two Gamma Processes”. Journal of Informatics and Mathematical Sciences, vol. 8, no. 1, Jan. 2016, pp. 1-16, doi:10.26713/jims.v8i1.326.