Today, if you're an expert, I would almost certainly recommend you the first hep-th paper by
In this setup, the features of particle physics are "geometrized" in terms of eight-real-dimensional manifolds as completely as it gets.
They study (complex) codimension one and two singularities and what they mean for the gauge groups, matter generations, and Yukawa couplings. Not surprisingly, given the name of the most senior author, they try to transform the analysis to a topological string theory case as much as possible.
But it is much more likely that their calculations of the number of generations etc. are correct than it was for some previous papers about the same topic that we discussed in 2007.
The second part of the paper is discussed here: