The Software Freedom Law Center has a publication that talks about file-scope copyright statements v. centralized ones: http://www.softwarefreedom.org/resources/2012/ManagingCopyrightInformation.html
The Software Freedom Law Center has a publication that talks about file-scope copyright statements v. centralized ones: http://www.softwarefreedom.org/resources/2012/ManagingCopyrightInformation.html