How do you access the routines documented in the PDF Accessibility API Reference?

[#1]

I am trying to use the accessibility features of the Adobe Acrobat SDK.  I have obtained the following document: PDF Accessibility API Reference, Adobe® Acrobat® DC SDK, May 2015. However, these routines do not appear in the Adobe Acrobat SDK header files, so I am unable to use them in my plug-in.  Is there another header and/or library that I need to download?  I have not been able to find such after extensive searching.

[#2]

I am trying to use the accessibility features of the Adobe Acrobat SDK.  I have obtained the following document: PDF Accessibility API Reference, Adobe® Acrobat® DC SDK, May 2015. However, these routines do not appear in the Adobe Acrobat SDK header files, so I am unable to use them in my plug-in.  Is there another header and/or library that I need to download?  I have not been able to find such after extensive searching.

[#3]

If you are talking about this document, but a later verion

https://www.adobe.com/content/dam/acom/en/devnet/acrobat/pdfs/access.pdf

It describes a COM interface for reading an accessible document. This interface is accessed from an external application outside Acrobat.  To use it you in include the "AcrobatAccess.idl" file as a resource in your Visual Studio project.

If you have downloaded the SDK, There's some documentation for it in the SDK AccessibilitySupport folder