On: The Art of Prolog, Second Edition

[jlarocco]

Although prototyped in Prolog, Erlang borrowed heavily from an obscure language called Strand.

https://en.wikipedia.org/wiki/Strand_(programming_language)

https://www.amazon.com/Strand-New-Concepts-Parallel-Programm...

I have a copy of the book, and the code samples are really similar to Erlang.