Challenges

• Semantic Textual Similarity 2013
• Semantic Textual Similarity 2012
• DARPA Semantic Textual Similarity (STS) Workshop
• [State of the art in paraphrase detection](http://aclweb.org/aclwiki/index.php?title=Paraphrase_Identification_(State_of_the_art\) )

Literature

• SemEval-2012 Task 6: A Pilot on Semantic Textual Similarity
• Papers from STS12
• Slides from DARPA Semantic Textual Similarity (STS) Workshop

Resources

• Stanford STS wiki
• RTE Knowledge Resources
• Babelnet New resource

Systems

TakeLab system

• The TakeLab Semantic Text Similarity System
• TakeLab paper

DKPro system

• DKPro system at Google Code UKP paper