Limonite from Montgomery County, Pennsylvania, USA
USA | |
| Boucot, Arthur James (1949) Notes on the Ecton Mine, Montgomery County, Pennsylvania. Rocks & Minerals, 24(9-10), 492-495. |
Smith, R. C. II (1977) Zinc and lead occurrences in Pennsylvania. Mineral Resource Report M72. Pennsylvania Geological Survey | |
| Lapham & Geyer, 1965. Mineral Collecting in Pennsylvania |
| The Mineralogy of Pennslvania - 1922 Samual Gordon pg. 216. |
| Mineralogy of Pennsylvania-1922 Samuel S. Gordon, pg. 217 |
| Mineralogy of Pennsylvania-1922 Samuel S. Gordon, pg. 218 |