The world coal-mining industry.
| Erakunde egilea: | |
|---|---|
| Formatua: | Liburua |
| Hizkuntza: | English |
| Argitaratua: |
Nendeln
Kraus Reprint
1975.
|
| Saila: | Studies and reports. Series B (Economic conditions)
nos. 31-32 |
| Gaiak: |