De Celis, E. A., De Guzman, L. A., & Javier, H. (2000). A methods engineering study on Goldwin Manufacturing Laboratories Corporation. College of Engineering.

De Celis, Excel Ann, Lorie Ann De Guzman, and Harold Javier. A Methods Engineering Study on Goldwin Manufacturing Laboratories Corporation. Diliman, Quezon City: College of Engineering, 2000.

De Celis, Excel Ann, et al. A Methods Engineering Study on Goldwin Manufacturing Laboratories Corporation. College of Engineering, 2000.