Scientific explanation of Skip Connections I am searching for scientific work on skip-connections.

Everybody is talking about improving gradient flow through the Network, which feels like it makes sense. But I would love to understand and read what that means when it comes down to the math. 

Other than the resnet paper I haven't found anything in depth about those magical skip-connections.

I am looking for any hints, papers or equations.
I recently read this paper which proposed a new technique without using skip-connections.It is proposed that the same accuracy can be achieved by increasing the width of the network rather than depth.