Burrows 2015, p. 51, Before the Tune-O-Matic. "First used in 1953, the Tune-o-matic fixed bridge unit was the invention of Gibson's then president, Ted McCarty, and it was designed to provide height adjustability and individual string intonation. In Conjunction with the fixed tailpiece, it quickly became established as Gibson's standard bridge on all but the cheapest solidbody electric."
Burrows 2015, p. 51, Over and Under. "During 1953, the trapeze bridge was replaced altogether with a "wrap-around stop bar". This looks similar to a standard Gibson tailpiece only it has integrated saddles with compensated alignment."
Burrows 2015, p. 50-51, Over and Under. "The original bridge used on the 1952 Goldtop was a trapeze [bridge] design which screwed to the base of the body and was only adjustable in overall height and length." ["wrap-under" design (1952) and "wrap-over" design (1952-1953)]
