He, Bo, Alain Togbé, and Shichun Yang. “A Note on the Diophantine Equation $|a^x-b^y|=c$”. MATHEMATICA SCANDINAVICA 107, no. 2 (December 1, 2010): 161–173. Accessed April 26, 2024. https://www.mscand.dk/article/view/15149.