Bittel, L. R. (1976). Improving supervisory performance. McGraw-Hill Company.
Dyfyniad Arddull ChicagoBittel, Lester R. Improving Supervisory Performance. New York: McGraw-Hill Company, 1976.
Dyfyniad MLABittel, Lester R. Improving Supervisory Performance. McGraw-Hill Company, 1976.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.