We would like to acknowledge the following sources for the images used on this website:

Child Development, 4th edition, Laura E. Berk, 1997, Allyn and Bacon, Massachusetts

Development across the Lifespan, Robert S. Feldman, 1997, Prentice Hall, New Jersey

Life-Span Development, 6th edition, John W. Santrock, 1997, Brown & Benchmark, Iowa

Human Development, 5th edition, James W. Vander Zanden, 1993, McGraw-Hill, Inc., New York