Extend README

README.rst

@@ -2,13 +2,17 @@
 sphinx-apipages
 ===============
 
-**sphinx-apipages** is a sphinx_ extension,
-that splits your API documentation
-into several sub-pages.
+**sphinx-apipages** is a sphinx_ extension
+for API documentation.
+It uses the autosummary_ and autodoc_ directives,
+and creates sub-pages
+for each function and class.
 
 Have a look at the installation_ and usage_ instructions.
 
 
+.. _autodoc: https://www.sphinx-doc.org/en/master/usage/extensions/autodoc.html
+.. _autosummary: https://www.sphinx-doc.org/en/master/usage/extensions/autosummary.html
 .. _installation: https://audeering.github.io/sphinx-apipages/install.html
 .. _sphinx: https://www.sphinx-doc.org/en/master/
 .. _usage: https://audeering.github.io/sphinx-apipages/usage.html