الأصناف الرئيسية
2X
الأقسام
الفروع
- 550Earth sciences
- 551Geology, hydrology & meteorology
- 552Petrology
- 553Economic geology
- 554Earth sciences of Europe
- 555Earth sciences of Asia1
- 556Earth sciences of Africa
- 557Earth sciences of North America
- 558Earth sciences of South America
- 559Earth sciences of other areas