TY  - BOOK
ED  - Indian Standards Institution                                                                                                                                                                                                                                   . 
TI  - Code of practice for sub surface exploration by pits, trenches, drifts and shafts, IS 4453-1980 / 
U1  - 622.142 
PY  - 1980///
CY  - New Delhi : 
PB  - Indian Standards Institution , 
ER  -