Event "1931 RCA demonstrates the first 33 1/3 LP's and players (using the same groove width as a 78rpm). They are withdrawn after a year. CBS (in the late 40's) completely reworks the process (microgroove) to make it functional. (Note: couldn't verify the date beyond "1931")"
1948 is the year that Columbia revived the 33 1/3 LP format. http://www.wired.com/thisdayintech/2010/06/0621first-lp-released/ http://en.wikipedia.org/wiki/LP_record
