APA
Vallen J. J. A. J. R. &. S. D. L., . (1968). The art and science of managing hotels / restaurants / institutions. Hayden book company, New Jersey: .
Chicago
Vallen Jerome J Abbey James R & Sapienza Dunnovan L, . 1968. The art and science of managing hotels / restaurants / institutions. Hayden book company, New Jersey: .
Harvard
Vallen J. J. A. J. R. &. S. D. L., . (1968). The art and science of managing hotels / restaurants / institutions. Hayden book company, New Jersey: .
MLA
Vallen Jerome J Abbey James R & Sapienza Dunnovan L, . The art and science of managing hotels / restaurants / institutions. Hayden book company, New Jersey: . 1968.