A swiftly tilting planet
Buku Teks
Moore, Patrick
The planet venus
Macmillan, 1958
Buku Teks
Who is responsible for our tilting pagodas?
Artikel Jurnal
Ballard, Robert D.
Exploring our living planet
National Geographic Society, 1983
Buku Referensi
Ahrens, L.H.
Distribution of the element in our planet
McGraw-Hill, 1965
Buku Teks SO