move package from VS2012 to VS2013

I have a VS2012 extension package that uses these references:
Microsoft.VisualStudio.Project.Utilities.v11.0
Microsoft.VisualStudio.Project.v11Only
Microsoft.VisualStudio.Project.VS.v11Only

All fine in VS2012. Now I want to port this for use in VS2013. I have upgraded the project to a VS2013 project and have VS2013 SDK installed. The VS2013 project builds fine, but does not run in VS2013 because these references do not exist. What should I use instead of these in VS2013?

Thanks, Jan

Jan