second book of two not recognized if it begins with a digit

[slukejones]

When using Pericope::parse, if the second book in a pair begins with a digit, then that digit will be included in the 1st pericope, and the second book won't be recognized. An example will clarify:
blah Acts 20:21; Exodus 5:1-14 blah
is parsed correctly, but
blah Acts 20:21; 2 Kings 5:1-14 blah
is parsed as "Acts 20:21, 2". This one is recognizably an error because the verses shouldn't decrease, but something like "Exodus 1:10-2:1; 2 Kings 5:1-14" would be trickier.
I've never seen a BNF for Bible verses, I would think that ';' can be used to separate blocks of verses, but only if it's not being used to separate whole pericopes.