Gaya APA
Leeuwen, A, T. (-1974).
Critique of earth. Gifford Lectures, 2nd series. .
Guildfort dsl:
Lutterworth Press.
Gaya MLA
Leeuwen, Arend, Th.van..
"Critique of earth. Gifford Lectures, 2nd series. ".
Guildfort dsl:
Lutterworth Press,
-1974.
Buku.