The Standard Model and The Four Dimensional Superstring
  Starting from the Nambu-Goto bosonic string, a four dimensional superstring model is constructed using the equivalence of one boson to two Majorana-Weyl fermions. The conditions of anomaly cancellation in a 'heterotic' string theory lead to the correct result and is found to be consistent with the requirements of the standard model. 
B.B.Deo and P.K.Jena
hep-th