Frye, Richard N.
Allen & Unwin , 1960
Buku Teks
Tregaskis, Richard
Holt, Rinehart and Winston, 1963
Buku Teks
Taylor, Richard
Englewood Cliffs : A Simon & Schuster, 1992
Buku Teks
Lauterbach, Richard E.
Harper & Brother Publishers, 1945
Buku Teks
Weston, Richard, author
Paidon Press Limited, 1995
Buku Teks