Licensing terms for source code in "Erlang and OPT In Action"

[Allan Streib]

Authors,

I bought your book after Erlang Camp last year, and have recently found
a project in which I think I could use the simple_cache application as a
starting point for a solution. However I can't find in the book any
terms under which that source code may be used as the basis for a
derivative work. Most of the source files on github include a copyright
by Martin Logan (and sometimes also Eric Merritt) but no other licensing
information.

Could any of you please clarify?

Thanks!
--
Allan Streib