Gaya APA
KUMMEL, B. (1961).
HISTORY OF THE EARTH: AN INTRODUCTION TO HISTORICAL GEOLOGY .
America:
W. H. Freeman and Company.
Gaya MLA
KUMMEL, Bernhard..
"HISTORY OF THE EARTH: AN INTRODUCTION TO HISTORICAL GEOLOGY".
America:
W. H. Freeman and Company,
1961.
Textbook.