I thought that looked like Simon Brown’s stuff.
He’s largely influenced by the “enterprise-y” stuff (hence UML).
I have yet to encounter any documentation or literature connected to the BEAM that used UML (not that it means anything) - more often than not it resorts to “whiteboard art”, e.g.:
However if you insist on using UML I’d recommend that you focus on Sequence and Activity diagrams aspects which are typically neglected in other, more mainstream contexts.
