Analysis of service operations cost for TDM and packet tandem networks. - David Tsay (Bell Labs Tech. J., 2000)

Metrics for comparative analysis of operations competency. - David Tsay; Elissa Pariser Matthews (Bell Labs Tech. J., 2005)

Economic analysis of class 5 migration to IMS. - Subramanian Prakash; Abdol Saleh; Salman Shaikh; David Tsay (Bell Labs Tech. J., 2007)