Bredow, Miriam, author
Gregg Publishing, 1959
Buku Referensi
Wisinski, Jerry, author
[American Management Association, ], 1999
eBooks
De Vries, Mary Ann, author
Prentice-Hall, 1991
Buku Referensi
Dany, Max, author
Hachette , 1977
Buku Teks
Jennings, Lucy Mae
Prentice-Hall, 1983
Buku Teks