“…Theoretical predictions for nucleon electromagnetic form factors, and for example, parton distribution functions, have been made using a variety of approaches, such as quark models [15][16][17][18][19][20][21][22][23][24][25][26], QCD sum rules [27], the Dyson-Schwinger equations [28][29][30] and lattice QCD simulations [31][32][33][34][35][36][37][38][39]. For the other elements of the octet, prior to lattice QCD computations, early work on the spectrum, electromagnetic form factors and weak form factors was based on, for example, the bag model [40][41][42][43][44][45][46][47][48][49][50][51], QCD sum rules [27], constituent quark models [52][53][54] and more recently the Dyson-Schwinger equations [55].…”