Holger Theisel Christian Rössl Hans-Peter Seidel Combining Topological Simplification and Topology Preserving Compression for 2D Vector Fields. 419-423 2003 conf/pg/2003 PG https://doi.org/10.1109/PCCGA.2003.1238287 https://doi.ieeecomputersociety.org/10.1109/PCCGA.2003.1238287 db/conf/pg/pg2003.html#TheiselRS03