|
USA | |
| Bernstein, L.R. (1976) Minerals of Washington D.C. and vicinity. U.S. Geological Survey Open-File Report 76-849, 183 pages. |
| Beard, R. (2015) Rockhounding Delaware, Maryland, and the Washington, DC Metro Area. Chapter 32: 122-123. |
| (2005) Mineral Resources Data System (MRDS), US Geological Survey. |
| Jeffrey W. Nagy (2017) The Mitchell Crystal - A Maryland Enigma. Rocks & Minerals Vol. 92, No. 2, 158-160 |
| (2005) Mineral Resources Data System (MRDS), US Geological Survey. |