|
USA | |
- Empire Mining District (Howes Gulch Mining District)
| USGS Prof Paper 223 |
| Eckel, Edwin Butt , Cobban, Robert R., Mosburg, Shirley K., Foord, Eugene E. (1997) Minerals of Colorado. Fulcrum Publishing. |
| (2005) Mineral Resources Data System (MRDS), US Geological Survey. |
| Lovering, T.S., Goddard, E.N. (1950) Geology and ore deposits of the Front Range, Colorado. Professional Paper 223. US Geological Survey doi:10.3133/pp223 |
| (2005) Mineral Resources Data System (MRDS), US Geological Survey. |
| (2005) Mineral Resources Data System (MRDS), US Geological Survey. Lovering, T.S., Goddard, E.N. (1950) Geology and ore deposits of the Front Range, Colorado. Professional Paper 223. US Geological Survey doi:10.3133/pp223 |
| Eckel, Edwin Butt , Cobban, Robert R., Mosburg, Shirley K., Foord, Eugene E. (1997) Minerals of Colorado. Fulcrum Publishing. |
| Eckel, Edwin Butt , Cobban, Robert R., Mosburg, Shirley K., Foord, Eugene E. (1997) Minerals of Colorado. Fulcrum Publishing. |
| Eckel, Edwin Butt , Cobban, Robert R., Mosburg, Shirley K., Foord, Eugene E. (1997) Minerals of Colorado. Fulcrum Publishing. |
| Eckel, Edwin Butt , Cobban, Robert R., Mosburg, Shirley K., Foord, Eugene E. (1997) Minerals of Colorado. Fulcrum Publishing. |
| Rocks & Minerals 59:11 |
- Spencer Heights-Poudre Falls Area
| (2005) Mineral Resources Data System (MRDS), US Geological Survey. |