Sliesoraitienė, R. “Analogue of the Mahler — Sprindžuk’s Theorem for Polynomials of the Second Degree in Two Variables”. Lithuanian Mathematical Journal 9, no. 3 (September 15, 1969): 627–634. Accessed May 7, 2024. https://www.journals.vu.lt/LMJ/article/view/20807.