Cassingham KM, Sills EO, Pattanayak SK, Mansfield CA. Voluntary conservation of North Carolina's natural heritage. J For. 2002;100(5):16-23.
McKenna SP, Whalley D, Doward LC. Which outcomes are important in schizophrenia? Int J Methods Psychiatr Res. 2000;9(1):S58-67.