Fundamentele wisselwerking: Verskil tussen weergawes

}}</ref><ref name="Weisstein">{{cite web |last=Weisstein |first=Eric W. |title=Fifth Force |work=World of Science |publisher=Wolfram Research |date=2007 |url=http://scienceworld.wolfram.com/physics/FifthForce.html |format= |doi= |access-date=14 September 2017 |language=en |archive-url=https://web.archive.org/web/20190531205847/http://scienceworld.wolfram.com/physics/FifthForce.html |archive-date=31 Mei 2019 |url-status=live |df=dmy-all}}</ref><ref name="Franklin">{{cite book

|+ '''Die vier fundamentele wisselwerkings van die natuur'''<ref>{{cite web |url=http://www.pha.jhu.edu/~dfehling/particle.gif |title=Standard Model of Particles and Interactions |author=<!--Staff writer(s); no by-line.--> |date= |website=jhu.edu |publisher=Johns Hopkins University |access-date=18 Augustus 2016 |quote=.gif |language=en |archive-url=https://web.archive.org/web/20161021050116/http://www.pha.jhu.edu/~dfehling/particle.gif |archive-date=21 Oktober 2016 |url-status=live |df=dmy-all}}</ref>