Gaya APA
Spencer, J., F. (2007).
SCIENCE MONTH BY MONTH PRACTICAL IDEAS AND ACTIVITIES FOR TEACHERS AND HOMESCHOOLERS .
USA:
Jossey Bass.
Gaya MLA
Spencer, Julia, Farish.
"SCIENCE MONTH BY MONTH PRACTICAL IDEAS AND ACTIVITIES FOR TEACHERS AND HOMESCHOOLERS".
USA:
Jossey Bass,
2007.
Buku Inti.