Hemphill’s Bookstore. 2nd ed. 1981, ISBN 0-914696-14-9 Pettijohn, F.J., P.E. Potter and R. Siever, 1987, Sand and sandstone, 2nd ed. Springer-Verlag. ISBN
Harvey, Philip D.; McClure, Margaret M.; Look, Amy E.; Leung, Winnie W.; Siever, Larry J. Vocational functioning in schizotypal and paranoid personality