1. Barnes R. M. Work Sampling 2nd ed. John Wiley & Sons Inc. New York N.Y. 1956.
2. Borcherding J. D. Productivity Improvement 10th Unit of the Associated General Contractors' Superintendent Training Program McKnight Publishing Company Bloomington Ill. 1979.
3. Chang L.‐M. and Borcherding J. D. “Craftsman Questionnaire Sampling for Construction Productivity ” Transactions of American Association of Cost Engineers June 1984 pp. H.2.1–H.2.4.
4. Evaluation of Craftsman Questionnaire