TY  - BOOK
AU  - Jackson,Donald Dale
ED  - Time-Life Books.
TI  - Underground  Worlds
PY  - 1982///
CY  - Alexandria, Va.
PB  - Time-Life Books
KW  - Caving
KW  - History
KW  - Caves
N1  - Bibliography: p. 170-172; Open access
ER  -