http://www.keesfloor.nl/artikelen/zenit/shiptrail/
http://pafc.arh.noaa.gov/classroom_ship_trails.php
http://iwonderproductions.com/cons.htm
http://www.sat.dundee.ac.uk/gif/lovely/shiptrails200111121319.ch1.jpg
http://www.spc.noaa.gov/coolimg/shiplume/shiploop.htm
http://www.nasa.gov/lb/multimedia/imagegallery/image_feature_355.html
http://www.chemtrailcentral.com/ubb/Forum14/HTML/000010.html