Echols, J. C. (1993). Tree homes: Teacher's guide. Great Explorations in Math and Science (GEMS).
Chicago-viite (17. p.)Echols, Jean C. Tree Homes: Teacher's Guide. Berkeley, CA: Great Explorations in Math and Science (GEMS), 1993.
MLA-viite (9. p.)Echols, Jean C. Tree Homes: Teacher's Guide. Great Explorations in Math and Science (GEMS), 1993.
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