Vic Stenger has uploaded a shorter version of one of his recently-published article tackling the natural origin of the universe.
Abstract: A mathematical model of the natural origin of our universe is presented. The model is based only on well-established physics. No claim is made that this model uniquely represents exactly how the universe came about. But the viability of a single model serves to refute any assertions that the universe cannot have come about by natural means.
As you recall, he wrote a rather "interesting" book that came out a few months ago called "God: the Failed Hypothesis". While he's not tackling that directly here, it is still along the same line of attack whereby he's arguing that there CAN be a possible scenario for the evolution of our universe without invoking anything else (such as supernatural interference) other than known physics.
I plan to read it more closely in the next few days.