Einstein-Yang-Mills-Dirac systems from the discretized Kaluza-Klein   theory
  A unified theory of the non-Abelian gauge interactions with gravity in the framework of a discretized Kaluaza-Kleine theory is constructed with a modified Dirac operator and wedge product. All the couplings of chiral spinors to the non-Abelian gauge fields emerge naturally as components of the couplings of the chiral spinors to the generalized gravity together with some new interactions. In particular, the currently prevalent gravity-QCD-quark and gravity-electroweak-quark-lepton models are shown to follow as special cases of the general framework. 
Ai Viet Nguyen, Van Dat Nguyen, Suan Han Nguyen and Kameshwar C. Wali
hep-th gr-qc