Kharisma, 2003
Buku Teks
SIAM (Society for Industrial and Applied Mathematics), 1990
Buku Referensi
Djohan
Perpustakaan Perguruan Kem. P.P. dan K., 1956
Buku Teks
Piaget, Jean
Hillsdale, New Jersey Lawrence Erlbaum Associates 1991,
Buku Teks
Jakarta Gramedia Pustaka Utama 2000,
Buku Teks