Publication
-
Elba Article
Gea, 2(2), 36-40.January 1969
-
Zaagmachine Article
Gea, 2(3), 41-44.January 1969
-
Kollektie-techniek Article
Gea, 2(3), 44-45.January 1969
-
Het meten van de helling Article
Gea, 2(3), 45-46.January 1969
-
Aardbevingen Article
Gea, 2(3), 46-46.January 1969
-
Korte inleiding in de Paleobotanie Article
Gea, 2(3), 47-52.January 1969
-
Over vindplaatsen Article
Gea, 2(3), 52-54.January 1969
-
Mammoeten in Nederland Article
Gea, 2(4), 68-68.January 1969