The wiki at http://wiki.nginx.org has been a useful resource for a number of years. Here you will find a complete directive reference, a module listing, and a number of configuration examples. Keep in mind though, that this is a wiki, and the information found on it is not guaranteed to be accurate, up-to-date, or to fit your needs exactly. As we have seen throughout this book, it is always important to think about what you want to accomplish before setting out to derive the solution.
NGINX, Inc. maintains the official reference documentation located at http://nginx.org/en/docs/. There are some documents introducing NGINX, as well as How-to's and pages describing each module and directive.