RefSeek introduces document search, definitions, natural language math calculations, and an expanded reference directory. Today's release expands upon RefSeek's core search offering, which returns relevant academic resources from around the Web while filtering out commercial content. Summary of new features: Document Search RefSeek's new document search engine is designed specifically for retrieval of non-HTML documents including Adobe PDFs and Microsoft Office files. Indexed documents are freely available and can be previewed without leaving RefSeek's search results page. Definitions RefSeek now provides searchers with definitions and synonyms for 150,000 words and phrases. Definitions are displayed alongside search results with links to complete entries at various online dictionaries. Math Calculations With the introduction of natural language math calculations, RefSeek users can find instant answers to complex math expressions and perform a broad range of unit conversions. For example, searching for "5 in binary" or "how many feet in a meter" will return a numeric result. Reference Directory RefSeek has expanded its Reference Directory, which features only the best online resources. RefSeek's directory includes hundreds of carefully selected reference sites in categories such as almanacs, bookmarking, dictionaries, and encyclopedias