Gaya APA
Vol.20, G, E, O, K.
(1993).
Grolier encyclopedia of knowledge Vol.20 / Grolier Incorporated
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Gaya MLA
Vol.20, Grolier, Encyclopedia, Of, Knowledge.
"Grolier encyclopedia of knowledge Vol.20 / Grolier Incorporated".
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,
1993.
Referensi.