Novak, David
Developmental mathematics
D.C. Health , 1989
Buku Teks SO
Developmental psychology
American Psychological Assosiation, 2001
Majalah, Jurnal, Buletin
Meicr, Richard L.
Developmental planning
McGraw-Hill, 1965
Buku Teks SO
Strommen, Ellen A.
Developmental psychology
Dorsey Press, 1983
Buku Teks SO
Fitagerald, Hiram E
Developmental psychology
0, 1982
Buku Teks