“Comedy is tragedy plus time” (theatre adage)

Entry in progress—B.P.
   
21 July 1958, Bakersfield (CA) Californian, pg. 21, col. 1:
Allen (Comedian Steve Allen—ed.) also has another formula for laughs: “Tragedy plus time plus the will to be amused equals comedy. If you don’t have the will to laugh, you won’t be amused—whether it’s by a Chaplin or anyone like him.”
 
23 November 1962, Salisbury (MD) Times, pg. 23, col. 3:
“They say that comedy is tragedy plus time. After getting the bills, I believe it.”
(Comedian Bob Newhart—ed.)
 
Google Books
Show: The Magazine of the Arts
Volume 3
1963
Pg. 116:
To her (Carol Burnett—ed.), “Comedy is tragedy mellowed by time.”