Entity Framework 4 Repository?

I am learning Entity Framework 4, and I want to use the Repository pattern to organize and isolate my persistence objects. I have done some research here and elsewhere on the web, and I am having a difficult time finding anything really useful on the subject. Most of the blogs look like simple ports of repositories from other ORM systems, with lots of contradictory advice. Most seem to pass the object context to the business layer, which would seem to defeat the purpose of a repository approach.

Can anyone suggest a good article, book, or blog the explains how to implement the Repository pattern with Entity Framework 4, without polluting the business layer with persistence objects? Thanks for yo开发者_Python百科ur help.

Here is a list of bookmarks I have about this topic. I prefer a combination of approaches given in these so unfortunately I don't have a single pick.

http://www.primaryobjects.com/CMS/Article122.aspx

https://github.com/geersch/EntityFrameworkObjectContext

http://blogs.microsoft.co.il/blogs/gilf/archive/2010/06/21/revisiting-the-repository-and-unit-of-work-patterns-with-entity-framework.aspx

http://blogs.msdn.com/b/adonet/archive/2009/06/16/using-repository-and-unit-of-work-patterns-with-entity-framework-4-0.aspx

http://huyrua.wordpress.com/2010/07/13/entity-framework-4-poco-repository-and-specification-pattern/

http://www.codeproject.com/KB/database/ImplRepositoryPatternEF.aspx

http://elegantcode.com/2009/12/15/entity-framework-ef4-generic-repository-and-unit-of-work-prototype/

http://www.mindscapehq.com/blog/index.php/2008/05/12/using-the-unit-of-work-per-request-pattern-in-aspnet-mvc/

http://mfelicio.wordpress.com/2010/02/07/managing-the-entity-framework-objectcontext-instance-lifetime-in-wcf-and-sharing-it-among-repositories/

http://www.west-wind.com/weblog/posts/246222.aspx