N. A. Vavilov, “Computers As a Novel Mathematical Reality: III. Mersenne Numbers and Sums of Divisors”, Dokl. Math., 107:3 (2023), 173
Joshua Zelinsky, “Upper bounds on the second largest prime factor of an odd perfect number”, Int. J. Number Theory, 15:06 (2019), 1183
Oleksiy Klurman, “Radical of perfect numbers and perfect numbers among polynomial values”, Int. J. Number Theory, 12:03 (2016), 585