World Facts : countries of the world
Gedes & Grosset, 2001
Buku Referensi
Johnson, George B.
the Living world
McGraw-Hill, Higher Education, 2008
Buku Teks
Stanier, Roger Y.
The microbial world
Prentice-Hall, 1963
Buku Teks
Gregory, J. N.
The world of radioisotopes
Angus & Robertson , 1966
Buku Teks
Johnson, George B.
The Living world
McGraw-Hill, 2003
Buku Teks