add a reference guide

README.md

@@ -176,6 +176,7 @@ to add support for the language of your choice and send a pull request!
 
 - [docs/tutorial.md](docs/tutorial.md): Using bcc tools to solve performance, troubleshooting, and networking issues.
 - [docs/tutorial_bcc_python_developer.md](docs/tutorial_bcc_python_developer.md): Developing new bcc programs using the Python interface.
+- [docs/reference_guide.md](docs/reference_guide.md): Reference guide to the bcc and bcc/BPF APIs.
 
 ### Networking
 

docs/tutorial_bcc_python_developer.md

@@ -2,7 +2,7 @@
 
 This tutorial is about developing [bcc](https://github.com/iovisor/bcc) tools and programs using the Python interface. There are two parts: observability then networking. Snippits are taken from various programs in bcc: see their files for licences.
 
-There is also a lua interface for bcc, and a tutorial for end-users of tools: [tutorial.md](tutorial.md).
+Also see the bcc developer's [reference_guide.md](reference_guide.md), and a tutorial for end-users of tools: [tutorial.md](tutorial.md). There is also a lua interface for bcc.
 
 ## Observability