Derksen: From Proto-Indo-European*(H)ruH-. Indo-European cognates include Old Norserýja(“to tear out wool”), Latinrūtacaesa(“minerals already dug up, timber already felled, when an estate is sold”). Derksen seems unwilling to include Vasmer's cognates due to his assumption of a laryngeal in the root, required in his view to account for the acute tone of the term.
Černyx, P. Ja. (1999), “рыть”, in Istoriko-etimologičeskij slovarʹ russkovo jazyka [Historical-Etymological Dictionary of the Russian Language] (in Russian), volume 2, 3rd reprint edition, Moscow: Russkij jazyk, page 131
Vasmer, Max (1964–1973), “рыть”, in Etimologičeskij slovarʹ russkovo jazyka [Etymological Dictionary of the Russian Language] (in Russian), translated from German and supplemented by Oleg Trubačóv, Moscow: Progress