The C# Language Specification for Asynchronous Functions (http://www.microsoft.com/en-us/download/details.aspx?id=23753 http://www.microsoft.com/en-us/download/

The C# Language Specification for Asynchronous Functions (http://www.microsoft.com/en-us/download/details.aspx?id=23753 http://www.microsoft.com/en-us/download/details.aspx?id=2375...) is available for download since 4/13/2011, and they have been many drafts before that.