Adding a native static library (.a) to Xamarin Mac project

I have a special build of sqlite - both .dylib and a handful of .a's. I would like to include the .a in my Xamarin Mac project. Is there documentation on how to do this properly.

My first attempt was to put the .a into the Native References folder and using DllImport("__Internal", ...) This is ideal for me, but it didn't work at all, and my executable did not increase in size suggesting that the .a were completely ignored. Putting the dylib into Native References also did not make DllImport("sqlite3", ...) work properly. By not working, I mean I get the EntryPointNotFoundException...

Any help anyone can give me on this would be much appreciated.