References

The meanings of the global warming

http://zfacts.com/p/49.html
http://www.iht.com/articles/2005/07/06/opinion/edsandalow.php
http://en.wikipedia.org/wiki/Global_warming

Water pollution

http://en.wikipedia.org/wiki/Water_pollution
http://www.umich.edu/~gs265/society/waterpollution.htm
http://www.units.muohio.edu/dragonfly/water/h2oindex.shtml


The meanings of the Colours

http://www.sibagraphics.com/colour.php

The meanings of the cross

http://www.inplainsite.org/html/meaning_of_the_cross.html