Bearden, James H.
Holt, Rinehart and Winston , 1969
Buku Teks
Din, Rasshied
Conran Octopus, 2000
Buku Teks
Din, Rasshied
Conran Octopus, 2000
Buku Referensi
Nau, Henry R., 1941-
SAGE Publications, 2019
Buku Teks
Kelley, Eugene J.
Irwin , 1967
Buku Teks