Persistent Trees in git, Clojure and CouchDB « EclipseSource Blog
http://eclipsesource.com/blogs/2009/12/13/persistent-trees-in-git-clojure-and-couchdb-data-structure-convergence
"This is a tale of three images. I found these images while investigating the internals of several different applications. There are some really neat software projects emerging at the moment, and as a developer I always find it interesting to take a look at the implementation details, because there is often a lot to be learned. It’s not always something you might need right now, but maybe a few years down the line you may be confronted with a similar problem. Plus – in my opinion – knowing a bit about the internals of a program helps reasoning about its behaviour."
Spinneret Query Language Primer
http://www.spinneret.org/doc/query-language.html
"This document briefly introduces SPQL (Spinneret Query Language). It will be updated as the language definition continues to be refined."