Jeffrey J. P. Tsai Steve Jennhwa Yang Yao-Hsiung Chang Timing Constraint Petri Nets and Their Application to Schedulability Analysis of Real-Time System Specifications. 32-49 http://www.computer.org/tse/ts1995/e0032abs.htm 1995 21 IEEE Trans. Software Eng. 1 db/journals/tse/tse21.html#TsaiYC95