Callaghan, J. (1992). Costing for contracts. Directory of cocial change.
Cita Chicago (17th ed.)Callaghan, John. Costing for Contracts. London: Directory of cocial change, 1992.
Cita MLA (8th ed.)Callaghan, John. Costing for Contracts. Directory of cocial change, 1992.
Atenció: Aquestes cites poden no estar 100% correctes.