Specifications fall under the same clause as standards (regardless of whether they are official standards or failed to acquire such a status). In your case, it's a standard retrieved from a database.
Identifying elements such as patent/standard numbers should be included
If no individual author is available, a corporate author can be used in the in-text reference
(Standards Australia 1994)
Reference List Entry:
Standards Australia 2008, Personal floatation devices - General requirements. AS 4758.1-2008. Available from: Standards Australia Online. [1 December 2008].
In your case, you have no author but a corporate entity: © 1999-2012 Microsoft Corporation. All rights reserved. The 'Details' entry on the download page gives: Date Published: 6/7/2013
An in-text citation would be:
(Microsoft Corporation 2013)
The Reference List Entry for, say, referencing the
false literals, would look like:
Microsoft Corporation, C# Language Specification Version 5.0: chapter 18.104.22.168 Boolean literals. Available from: http://www.microsoft.com/en-us/download/details.aspx?id=7029 [7 June 2013]