I just found a great blog post by Martin Kleppmann titled Accounting for Computer Scientists, a succinct introduction to double-entry accounting (although he doesn’t refer to it as such) in terms of basic graph theory:

Eventually I figured it out: basic accounting is just graph theory. The traditional ways of representing financial information hide that structure astonishingly well, but once I had figured out that it was just a graph, it suddenly all made sense.

He goes on to illustrate how a profit-and-loss statement and a balance sheet can be visualized on a simple DAG.  Good stuff…