Hui Liu, Wei Zhong Shao, Lu Zhang, and Zhi Yi Ma, "Detecting Overlapping Use Cases," IET Software, Vol. 1, No. 1, February  2007, pp. 29-36.

@article{HuiLiuIET07,

  author    = {Hui Liu and Wei Zhong Shao and Lu Zhang and Zhi Yi Ma},

  title     = {Detecting Overlapping Use Cases},

  journal   = {IET Software},

  volume    = {1},

  number    = {1},

  year      = {2007},

  pages     = {29-36}

}