Josiah Edward Spurr: Geology Applied To Selenology. Band II: The Features of the Moon. Science Press Printing Co., Lancaster, PA, 1945, S. 20 (HathiTrust)
usgs.gov
pubs.er.usgs.gov
Don E. Wilhelms: The geologic history of the Moon. USGS Professional Paper 1348, Department of the Interior, U.S. Geological Survey, Washington, D.C., 1987, S. 83 ff. (USGS)