APA Publications, [date of publication not identified]
Buku Referensi
World Express Mapping Sdn. Bhd, [date of publication not identified]
Buku Referensi
Haworth, Lawrence
Indiana University Press, 1963
Buku Teks
Banduningsih Rahayu
Fakultas Matematika dan Ilmu Pengetahuan Alam Universitas Indonesia, 2011
UI - Skripsi (Open)
Tuttle, 2011
Buku Referensi