's suggestion that the separator should be qr/ - /, and only use the first two fields, the Milne entry would not be an exception. 'Series' fields would still be a problem. Neither your text nor your code tell us anything about how you might recognize them. You have not even provided a single example. Of course, you could avoid this problem by using the last field instead of the second. Then Milne would be a problem again, not because of the extra hyphens, but because it does not fit the format.