edited by Victor Chew
John Wiley & Sons, 1958
Buku Teks
Morse, Janice M., author
Routledge, 2009
eBooks
Cochran, William G., author
John Wiley & Sons, 1957
Buku Teks
Yin, Robert K., author
Sage, 1994
Buku Teks
Yin, Robert K., author
Sage, 2003
Buku Teks