Savitch, Walter J., author
The Benjamin/Cummings Publishing, 1984
Buku Teks
Page one publishing pte ltd, 2011
Buku Referensi
Ulene, Art
Mindanao way Health Points , 1998
Buku Teks
Hodnett, Edward
Harper & Brothers, 1955
Buku Teks
Brown, Arthur W., author
Twayne Publishers, 1964
Buku Teks