Referencias

• http://geografia.laguia2000.com/general/morrena

• http://vocabulariogeografico.blogspot.com/2011/12/morrena.htm

• https://www.ecured.cu/Morrenas

• http://www.lateinamerika-studien.at/content/natur/naturesp/natur-615.html

• http://en.bab.la/dictionary/spanish-english/morrena

• https://es.wikipedia.org/wiki/Wikipedia:Portada