De Guzman, P. E., & Robles, K. C. (2006). The role of contractual employment in the business firms and impact on the employees. University of the Philippines Diliman Extension Program in Pampanga.

De Guzman, Priscilla E., and Kathyrine C. Robles. The Role of Contractual Employment in the Business Firms and Impact on the Employees. Pampanga: University of the Philippines Diliman Extension Program in Pampanga, 2006.

De Guzman, Priscilla E., and Kathyrine C. Robles. The Role of Contractual Employment in the Business Firms and Impact on the Employees. University of the Philippines Diliman Extension Program in Pampanga, 2006.