Cassingham KM, Sills EO, Pattanayak SK, Mansfield CA. Voluntary conservation of North Carolina's natural heritage. J For. 2002;100(5):16-23.
Sorensen HT, Sabroe S, Olsen J, Rothman KJ, Gillman MW, Fisher P. Birth weight as a predictor of young men's intelligence. A historical cohort study. Ugeskr Laeger. 1999 Feb 8;161(6):791-3.
Gray-Little B, Williams VSL, Hancock TD. An item response theory analysis of the Rosenberg self-esteem scale. Pers Soc Psychol Bull. 1997;23(5):443-51. doi: 10.1177/0146167297235001