Hul, S., Ng, D. K. S., Tan, R. G. R., Chiang, C. L., & Foo, D. C. Y. (2007). Crisp and fuzzy optimisation approaches for water network retrofit. Animo Repository.

Hul, Seingheng, Denny K. S. Ng, Raymond Girard R. Tan, Choon Lai Chiang, و Dominic C. Y. Foo. Crisp and Fuzzy Optimisation Approaches for Water Network Retrofit. Animo Repository, 2007.

Hul, Seingheng, et al. Crisp and Fuzzy Optimisation Approaches for Water Network Retrofit. Animo Repository, 2007.