Tests of Strength of Roof Supports Used in Anthracite Mines of Pennsylvania
| Year: | 1929 |
|---|---|
| Document Type: | N/A |
| Issuing Agency: | United States. Bureau of Mines. |
| Series: | United States Bureau of Mines Reports |
| Report Number: | Bulletin 303 |
| Link: | https://digital.library.unt.edu/ark:/67531/metadc12476/ |