@Article{LIS16,<br>title = {On Multiple Moving Objects},<br>author = {Michael Erdmann and Tomas Lozano-Perez},<br>year = {1986},<br>url = {http://lis.csail.mit.edu/pubs/tlp/multiple-moving.pdf},<br>journal = {Algorithmica},<br>volume = {2},<br>pages = {1419--1424},<br>}