References
- American Geological Institute. 1977 . Investigating the Earth , 302 – 304 . Boston : Houghton Mifflin Company .
- Chiappetta , Eugene L. and Collete , Alfred T. 1986 . Science instruction in the middle and secondary schools , 56 – 62 . Columbus , OH : Charles E. Merrill Publishing Company .
- Daley , Robert E. , Higham , W. John. and Matthias , George F. 1978 . Earth science: A study of a changing planet , 62 – 65 . Fairfield , NJ : Cebco Standard Publishing .
- Earth Science Curriculum Project. 1965 . Stereo atlas , Northbrook , IL : Hubbard Press . plate 27