What are the best open source resources for automatic document summarization?

What are the best open source resources for automatic document summarization?

I would like to know the answer to this question myself; but, this is a contest that’s only just begun, much less been definitively decided. Beyond the Wikipedia entry on Automatic summarization and the Quora topic on Automatic Summarization, here are some additional resources:

See summarizers:
· Copernic Summarizer | Meta-Guide.com
· DiaSumm (Dialog Summarizer) | Meta-Guide.com
· GistSumm (GIST SUMMarizer) | Meta-Guide.com
· Open Text Summarizer | Meta-Guide.com

See also book Contents:
· Automatic Summarization (2011) .. by Ani Nenkova & Kathleen McKeown
· Proceedings of the Workshop on Automatic Text Summarization 2011 .. Canadian AI, St. John’s, Newfoundland