[Proceedings of a] seminar-workshop on non-metallic mineral resources development, Nayong Kalikasan, Caliraya, Laguna, Nov. 8-9, 1978
| Egile korporatiboa: | , |
|---|---|
| Formatua: | Liburua |
| Hizkuntza: | English |
| Argitaratua: |
[S.l.
s.n.
1979n]
|
| Gaiak: |