@article{SSZL05,
 author = {Sheng, Weiguo and Swift, Stephen and Zhang, Leishi and Liu, Xiaohui},
 journal = {IEEE Transactions on Systems, Man, and Cybernetics—Part B: Cybernetics},
 month = {dec},
 number = {6},
 pages = {1156-1167},
 title = {A Weighted Sum Validity Function for Clustering With a Hybrid Niching Genetic Algorithm},
 volume = {35},
 year = {2005}
}