Roberts, Sharon L.
Appleton Century Crofts, 1986
Buku Teks
Roberts, Sharon L.
Prentice-Hall, 1985
Buku Teks
edited by Edward D. Sivak, Thomas L. Higgins, Adam Seiver
William & Wilkins, 1995
Buku Referensi
Robertson, John A.
Bantam Books, 1983
Buku Teks
edited by Mary Fran Hazinski.
Elsevier/Mosby, 2013
Buku Teks