API reference documentation for .Net libraries for Classic OPC|Classic OPC: DA, A&E, HDA, XML-DA, etc.|Forum|OPC Foundation

As a registered user, I'm allowed to download the Core Components from https://opcfoundation.org/deve.....ls-classic. This includes the DLLs that allow me to write a .Net application to access a server using HDA. But I can't find any OPC Foundation API documentation for the classes and methods in the library.

As an example of the kind of information I'm after, it looks like this Technosoftware product is similar, and there is some documentation for that (e.g. ReadProcessed), although it isn't very detailed - on that page for example, it doesn't define the units for "resampleInterval" (seconds, minutes, etc.) 

I wonder if anyone can suggest where to find this API documentation, please. Thanks!