2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/132256Following the treatment of Blass and Sagan, we present an algorithmic bijection between the Eulerian equivalence classes of totally cyclic orientations and the spanning trees without internal activity edges for a given graph.10 pages, 2 figuresCombinatorics05A99, 05C20text