Tony Rivera
Biography:
Tony came into the cartoon business in the middle thirties, worked at one of Grim Natwick's assistants on "Snow White and the Seven Dwarfs," walked out on strike at Disney's in 1941 and thereafter worked at almost every animation studio of note until his retirement half a century later.-http://animationguildblog.blogspot.com/2006/08/remembering-tony-rivera.html