Citations

http://www.windows2universe.org/earth/Atmosphere/clouds/cirrostratus.html
http://www.windows2universe.org/earth/Atmosphere/clouds/stratus.html
http://ww2010.atmos.uiuc.edu/(Gh)/guides/mtr/cld/cldtyp/hgh/crs.rxml
http://eo.ucar.edu/webweather/cumulus.html
http://www.windows2universe.org/earth/Atmosphere/clouds/altostratus.html
http://mmem.spschools.org/grade5science/weather/cirrocumulus.html