"up quark." YourDictionary, n.d. Web. 19 September 2018. <http://www.yourdictionary.com/up-quark>.
up quark. (n.d.). Retrieved September 19th, 2018, from http://www.yourdictionary.com/up-quark
The flavor of quark that has a charge of +23 and a mass estimated at three to six times that of an electron, belongs to the first generation of elementary fermions, and is a component of nucleons and other hadrons.