TruthUtils → AtlasHepMC Relation

File in Generators/TruthUtils	Includes file in Generators/AtlasHepMC
TruthUtils / MagicNumbers.h	AtlasHepMC / GenEvent.h
TruthUtils / MagicNumbers.h	AtlasHepMC / GenParticle.h
TruthUtils / MagicNumbers.h	AtlasHepMC / GenVertex.h