Change

[https://books.google.com/books?id=1zmZyr-ExYMC&pg=PA137 J. Bowyer Bell, Irving Louis Horowitz (2005) ''Assassin: Theory and Practice of Political Violence'', pp137, Transaction Publishers, ISBN 1-4128-0509-0]

to

[https://books.google.com/books?id=1zmZyr-ExYMC&pg=PA137 J. Bowyer Bell, Irving Louis Horowitz (2005) ''Assassin: Theory and Practice of Political Violence'', pp137, Transaction Publishers], ISBN 1-4128-0509-0

Per @Bgwhite "Using Wikipedia search to find "ISBN 978-123456789]" (insource:/ISBN [0-9]+/]/). I get 159 articles. There must be a ton of ISBNs in the middle of the link and not at the end."

For starts, let's do this only when ISBN is at the end. Too risky to do something else right now.