Washington U.S. Department of Health, Education, and Welfare 1955
Buku Teks
Spanbauer, Stanley J.
ASQC Quality Press, 1993
Buku Teks
Frederick, Robert W.
USA Appleton 1947
Buku Teks
Tokyo, Nanzan University, 2003
Majalah, Jurnal, Buletin
[place of publication not identified]: Higher education Bureau, Ministry of Education, Science and Culture 1984,
Buku Teks