"Etruscan Leopards and Lions," by Cornelius Vermeule, from the journal Bulletin of the Museum of Fine Arts, Vol. 59, No. 315 (1961), pp. 13-21, in 10 searchable pdf pages, with many plates. In this article, curator and art historian Cornelius Vermeule (Wikipedia) suggests an Asia Minor source for the Etruscan sculptures described, which date from the 7th-6th centuries B.C. Internet Archive has a selection of works by the author.