De Vries, Mary Ann
Prentice-Hall, 1991
Buku Referensi
Doris, Lillian
Prentice-Hall, 1960
Buku Teks
Bredow, Miriam
Gregg Publishing, 1959
Buku Referensi
Becker, Esther R.
Harper & Row, 1971
Buku Referensi
Stroman, James
American Management Association, 2008
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