TY  - BOOK
AU  - Onika, Dmitriæi Grigor§evich.
TI  - Excavation of mine openings
U1  - 622.2 
PY  - 1972///
CY  - Moscow
PB  - Mir Publishers
KW  - Shaft sinking
KW  - Coal mines and mining
N1  - Rev. translation of Provedenie gornykh vyrabotok; Icludes bibliographical references: p. [448]-449
ER  -