I am looking for a corpus containing documents for extractive summarization. The sentences of the documents should be labelled as "positive" if that sentence is included in the summary, "negative" otherwise. The sentences will be fed as training data for the summarizer I am currently working with.
You should look at TAC summarization track :
http://www.nist.gov/tac/2011/Summarization/index.html (2008..2011)
Another option : DUC data :
http://duc.nist.gov/data.html with manually created summaries.
I think NTCIR 2 & 3 have a corpus like this (positive sentences):
http://research.nii.ac.jp/ntcir/data/data-en.html
You may check, also, Multiling2015 corpus (the summaries are manual)
MSS task:
http://multiling.iit.demokritos.gr/pages/view/1532/task-mss-single-document-summarization-data-and-information
MMS task:
http://multiling.iit.demokritos.gr/pages/view/1540/task-mms-multi-document-summarization-data-and-information