Tobias Salzbrunn Christoph Garth Gerik Scheuermann Joerg Meyer Pathline predicates and unsteady flow structures. 1039-1051 2008 24 The Visual Computer 12 http://dx.doi.org/10.1007/s00371-007-0204-x db/journals/vc/vc24.html#SalzbrunnGSM08