| Author: | Halstead, Perry N. | 
|---|---|
| Additional Authors: | Hubbard, S. Jackson., Call, Richard D. | 
| Year: | 1968 | 
| Document Type: | BMRA | 
| Issuing Agency: | U.S. Dept. of the Interior, Bureau of Mines, | 
| SUDOC: | I 28.23:7097 | 
| Series: | Report of investigations / United States Department of the Interior, Bureau of Mines ; | 
| Report Number: | 7097 | 
| Subjects: | Boring | 
| Angles (Geometry)--Measurement | |
| Link: | https://hdl.handle.net/2027/mdp.39015078530667 |