Badings, A. H. L. (1901). "gek". Nieuw Hollandsch-Maleisch, Maleisch-Hollandsch Woordenboek. Tjeenk Willink. m/s. 89 – melalui Delpher. ...ook van vreugde, enz. – gila.
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"Dictionary: Geek". Dictionary.com-Merriam-Webster entry. Dicapai pada 2007-10-12.