AsDoc may be complicated with all its parameters, when dealing with external libraries.
A nice way I found it works is to use the -library-path parameter; this way the libraries will be included but they won't be documented.
For example:
asdoc -source-path "c:\MyProject\src" -doc-sources "c:\MyProject\src" -library-path "c:\MyProject\lib" -main-title "Pong" -output "c:\MyProject\doc"
Being c:\MyProject\lib
where you store all the libraries your project needs.