Gudmundsson, J.S.; Johnson, S.E.; Horne, R.N.; Jackson, P.B. & Culver, G.G. Doublet Tracer Testing in Klamath Falls, Oregon, article, December 15, 1983; (https://digital.library.unt.edu/ark:/67531/metadc876446/m1/1/: accessed November 15, 2018), University of North Texas Libraries, Digital Library, digital.library.unt.edu; .