Bukor, Jozsef, et al. “On the Diophantine Equation x_1x_2···x_n = h(n)(x_1 + x_2 +. + x_n)”. Annales Mathematicae Silesianae, vol. 12, Sept. 1998, pp. 123-30, https://journals.us.edu.pl/index.php/AMSIL/article/view/14169.