Sjokolade: Verskil tussen weergawes

<ref name="powis">{{Cite journal |last=Powis |first=Terry G. |last2=Cyphers |first2=Ann |last3=Gaikwad |first3=Nilesh W. |last4=Grivetti |first4=Louis |last5=Cheong |first5=Kong |date=24 May 2011 |title=Cacao use and the San Lorenzo Olmec |url=http://www.pnas.org/content/108/21/8595 |journal=Proceedings of the National Academy of Sciences |language=en |volume=108 |issue=21 |pages=8595–8600 |doi=10.1073/pnas.1100620108 |issn=0027-8424 |pmid=21555564 |pmc=3102397|bibcode=2011PNAS..108.8595P }}</ref>

 

 

<ref name="Kennis">Kennis, vol 6, 1980, bl. 1052-1053, ISBN 0 7981 0828 2</ref>