[Manichean]

Originally Posted by leehach

(?P<author>[^_]+)(,? ?e?t? ?a?l?) (?P<published>\d{4}) - (?P<title>[^_]+)
  -or-
(?P<author>[^_]+)(, et al|) (?P<published>\d{4}) - (?P<title>[^_]+)

I'd use the second, albeit for purely aesthetical reasons.