แหล่งที่มา:

http://www.school.net.th/library/create-web/10000/science/10000-829.html
http://www.kik5.com/index.php?option=com_content&view=article&id=112:5&catid=38:-5-dna&Itemid=59
http://guru.sanook.com/search/knowledge_search.php?q=%CA%D2%C3%BE%D1%B9%B8%D8%A1%C3%C3%C1+%CB%C3%D7%CD%B4%D5%E0%CD%E7%B9%E0%CD+(DNA)&select=1
http://guru.sanook.com/search/knowledge_search.php?q=%CA%D2%C3%BE%D1%B9%B8%D8%A1%C3%C3%C1+%CB%C3%D7%CD%B4%D5%E0%CD%E7%B9%E0%CD+(DNA)&select=1