A class to provide lineage information across lifecycle events through a pointer or set of pointers into the event(s), contract(s) and, possibly, payout components that the event is dependent on or relates to. As an example, if an contractFormation event is corrected, the correction event will have a lineage into the initial event, which takes the form of a globalKey into that initial contract formation event. Two referencing mechanisms are provided as part of the CDM: either the globalKey, which corresponds to the hash value of the CDM class which is referred to, or a reference qualifier which is meant to provide support for the ingestion of xml documents with id/href mechanisms. The CDM recommends the use of the globalKey and provides a default implementation which is accessible in the generated code through org.isda.cdm.globalKey.GlobalKeyHashCalculator. If implementers want to use an alternative hashing mechanism, the API in which they need to plug it is com.rosetta.model.lib.HashFunction.