Douglass, AE. 1933. ?Evidences Of Cycles In Tree Ring Records?. Proceedings Of The National Academy Of The Sciences. Proceedings Of The National Academy Of The Sciences.

of Washington, Carneigie Institution. 1929. ?Reports On The Conferences Of Cycles?. Washington, D.C. : Carneige Institution.

Douglass, AE. ?Dendrochronology And Studies In Cyclics?. University Of Pennsylvania Bicentennial Conference Proceedings. University Of Pennsylvania Bicentennial Conference Proceedings.