SUBJECT
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Natural resources
1
Nature
2
Nautical charts
1
Philosophy
2
Physical geograph
1
Physical geography
Pollution
2
Research
2
Rivers
1
Social conditions
2
Star Mountains
1
Storms
1
Study and teaching
1
Study and teaching (Higher)
1
Text-b00ks
1
Text-books
6
Textbooks
4
Weather
1
Weather control
1