A small resource, which may help you - http://thescipub.com/PDF/jcssp.2016.178.190.pdf
I am currently (and for some time actually) interested into the same problem. Summarization of text. It is a hard one to master. Not a lot of work has been done. I will be happy to be of any help.
(Bonus - a recently published paper about extractive summarization - https://arxiv.org/abs/1708.04439)