TY  - BOOK
AU  - Proctor, Robert Videtto
AU  - White, Thomas Lester
TI  - Rock tunneling with steel supports
AV  - TF 232 P71r
PY  - 1946///
CY  - Youngstown, Ohio
PB  - [s.n.]
KW  - Tuneles, Perforación de
KW  - Tectónica
ER  -