TY  - PP
AU  - Janssen, J. L.
AU  - Jansen, F. J.
AU  - Scheepmaker, H. W.
TI  - Erts
PY  - 1950///] -
CY  - [S-Gravenhage?]
PB  - J.L. Janssen
KW  - Vulcanologia
KW  - 551.21(051)
PB  - J.L. Janssen
A2  - Janssen
A2  - Jansen
A2  - Scheepmaker
PP  - [S-Gravenhage?]
SP  - Il.
ER  -