World Facts : countries of the world
Gedes & Grosset, 2001
 Buku Referensi
Forrester, Jay Wright
World dynamics
Wright-Allen Press, 1973
 Buku Teks
Ferris, Brian
World problems
Hulton Educational Publications, 1973
 Buku Teks
Johnson, George B.
the Living world
McGraw-Hill, Higher Education, 2008
 Buku Teks
Stanier, Roger Y.
The microbial world
Prentice-Hall, 1963
 Buku Teks