Katcher, Bruce Leslie
30 reasons employees hate their managers: what your people may be thinking and what you can do about it
American Management Association, 2007
 eBooks
Seligman, Eustace
What the United States can do about India
New York University Press, 1956.
 Buku Teks
Sant, Tom
The giants of sales : what Dale Carnegie, John Patterson, Elmer Wheeler, and Joe Girard can teach you about real sales success
American Management Association, 2006
 eBooks
Coon, Horace
Speak better write better English : what you can do with words; what words can do for you / Horace Coon
A Signet Key Book, 1954
 Buku Teks SO
service quality and customer satisfaction do matter
 Artikel Jurnal