Manfred Reichert Stefanie Rinderle-Ma Peter Dadam Flexibility in Process-Aware Information Systems. 115-135 2009 2 T. Petri Nets and Other Models of Concurrency http://dx.doi.org/10.1007/978-3-642-00899-3_7 journals/topnoc/2009-2 db/journals/topnoc/topnoc2.html#ReichertRD09