TY  - BOOK
AU  - Twenhofel,William H.
TI  - Soil, the most valuable mineral resource,: its origin, destruction and preservation,
T2  - Oregon. State Dept. of Geology and Mineral Industries. Bulletin
AV  - QE155 .A3 no. 26
U1  - 631.45 
PY  - 1944///]
CY  - [Portland
KW  - Erosion
KW  - Soil conservation
N1  - Reproduced from type-written copy; "References cited": p. [46]-[47]
ER  -