My sources

http://www.google.com/

http://en.wikipedia.org/wiki/Cloud

http://www.enchantedlearning.com/cgifs/clouds.GIF

http://www.free-online-private-pilot-ground-school.com/images/cloud-types.gif

http://www.dask.org.tr/english/want_to_know/meteorology/moisture/water-cycle.gif