Upstream Documentation

https://metacpan.org/pod/Marpa::R2

https://metacpan.org/pod/Marpa::R2#Other-documents

http://jeffreykegler.github.io/Marpa-web-site/libmarpa_api/latest/api_one_page.html

http://jeffreykegler.github.io/Marpa-web-site/libmarpa_api/stable/api_one_page.html