For more information on the guidelines this rule enforces, see the following external resources:
Capitalization Conventions, Design Guidelines for Developing Class Libraries
http://msdn2.microsoft.com/en-us/library/ms229043.aspx
Page 36, Framework Design Guidelines: Conventions, Idioms and Patterns for Reusable .NET Libraries
Krzysztof Cwalina and Brad Abrams
http://www.amazon.com/gp/product/0321246756/002-6248839-4752853?v=glance&n=283155