"Alan Blumlein – the man who invented stereo". AbbeyRoad. Retrieved 2009-05-18. In his short life, Blumlein devised over 120 patents and is considered one of the most significant engineers of his time.
GB patent 394325, Alan Dower Blumlein, "Improvements in and relating to Sound-transmission, Sound-recording and Sound-reproducing Systems.", issued 14 June 1933, assigned to Alan Dower Blumlein and Musical Industries, Limited