[R] Looking for a survey on text summarization techniques

I'm looking for a survey paper or a kind of resource that defines the problem well (text summarization) and discuss the approaches and models developed to solve it so far.

Through google, I've got some papers behind paywalls and others that weren't what I'm looking for.
So your input/suggestion will definitely help!

Thanks in advance!

machinelearning summarization survey text text summarization