«Abdus Salam - Nobel Lecture: Gauge Unification of Fundamental Forces». www.nobelprize.org. Consultado el 19 de enero de 2017. «The greatness of gauge ideas - of gauge field theories - is that they reduce these two quests to just one; elementary particles (described by relativistic quantum fields) are representations of certain charge operators, corresponding to gravitational mass, spin, flavour, colour, electric charge and the like, while the fundamental forces are the forces of attraction or repulsion between these same charges».
«Abdus Salam - Nobel Lecture: Gauge Unification of Fundamental Forces». www.nobelprize.org. Consultado el 19 de enero de 2017. «A third quest seeks for a unification between the charges (and thus of the forces) by searching for a single entity, of which the various charges are components in the sense that they can be transformed one into the other».
