@article {Zhang.2004.5,
	title = {Handoff Counting in Hierarchical Cellular System With Overflow Scheme},
	journal = {Computer Networks},
	volume = {46},
	number = {4},
	year = {2004},
	month = {Nov.},
	pages = {541-554},
	author = {Zhang, Yan and Soong, B.}
}
