ragalie/lisbn — pull request #2 by jelder (2013-10-18 17:39:03+00:00)
Title: Lisbn.extract()

This adds a helper method to find valid ISBNs within blocks of text.

```ruby
Lisbn.extract("Long form text mentioning several ISBNs including 978-0-07-352550-1") #=> ["978-0-07-352550-1"]
```