Current $verse_regex
\d{1,3}(?::\d{1,3})?(?:\s?(?:[-&,]\s?\d+))*

http://plugins.trac.wordpress.org/ticket/447
\d{1,3}(?::\s?\d{1,3})?(?:\s?(?:[-&,]\d{1,3}:?\d{0,3}))*

http://plugins.trac.wordpress.org/ticket/349
(?:\d{1,3}(?::\d{1,3})?(?:\s?(?:[-&,]\s?\d+))*(?:;)*)+