Springhouse , 1999
Buku Teks
edited by Jaime L. Stockslager
Lippincott Williams & Wilkins, 2003
Buku Referensi
Humphrey, Carolyn J. , author
An Aspen , 1998
Buku Teks
Fleschner Publishing Company, 1986
Buku Teks
foreword by Kathleen Fletcher
Springhouse , 2000
Buku Referensi