Simonetti L, Gardón JC, Ramos G. Residual levels on medroxyprogesterone acetate (MAP) impregnated sponges after estrus synchronization treatment in cyclic ewes. Braz. J. Vet. Res. Anim. Sci. 1999;36(5):240-243. doi:10.1590/S1413-95961999000500003