All the Revit SDKs are provided in the Revit Developer Centre:
http://www.autodesk.com/developrevit
Autodesk only provides support going back three releases.
What in heavens name would you want to program for Revit 2014?
In any case, you do not need the SDK to program for Revit.
All the API functionality is provided by the Revit API assemblies included with Revit.exe.
If you have Revit 2014 running, you already have the Revit API assemblies installed and can use those.
All the SDK provides in addition to that is documentation and samples.
Best regards,
Jeremy
Thanks. I should've been more specific, but what I'm looking for is the documentation, the Revit 2014 API reference guide (chm file).
Yes, that helps.
In that case, you are in luck:
The Revit API reference documentation help file contents are available online:
http://thebuildingcoder.typepad.com/blog/2016/08/online-revit-api-docs-and-convex-hull.html#2
Revit 2015, 2016, 2017: http://www.revitapidocs.com
Revit 2014: http://revitapisearch.com
Cheers,
Jeremy