Plagiarism
http://education.indiana.edu/~frick/plagiarism/item1.html
http://plagiarism.arts.cornell.edu/tutorial/principles.cfm

Purdue Academic Integrity
http://www.purdue.edu/odos/osrr/integrity.htm
The Purdue Online Writing Lab (OWL)
http://owl.english.purdue.edu/
The Purdue Online Writing Lab -evaluating sources
http://owl.english.purdue.edu/owl/printable/553/
Purdue University Libraries CORE tutorial
http://gemini.lib.purdue.edu/core/
Google scholar
http://scholar.google.com/
Purdue Libraries
http://www.lib.purdue.edu/

Sources you can find information about Purdue

Purdue News Service
http://news.uns.purdue.edu/
Purdue Exponent
http://www.purdueexponent.org/
Purdue Data Digest
http://www.purdue.edu/DataDigest/
Journal and Courier
http://www.jconline.com/apps/pbcs.dll/frontpage

APA Formating and Style Guide
http://owl.english.purdue.edu/owl/resource/560/01/
MLA Formating and Style Guide
http://owl.english.purdue.edu/owl/resource/557/01/