Ljunggren, Wilhelm. β€œOn an Improvement of a Theorem of T. Nagell Concerning the Diophantine Equation $Ax^3 + By^3 = C$”. MATHEMATICA SCANDINAVICA 1 (December 1, 1953): 297–309. Accessed December 5, 2025. https://www.mscand.dk/article/view/10388.