Last modified: 2007-07-19 11:31:11 UTC
Please refer to the link I provided. ISBN codes are all typed in the same way (as far as I could test it) but only a few of them are converted to links. I cannot figure if this is a bug with the ISBNs entered or the parser.
I fixed the problem with http://fa.wikipedia.org/w/index.php?title=%D9%85%D8%B5%D8%B7%D9%81%DB%8C_%DA%A9%D9%85%D8%A7%D9%84_%D9%BE%D9%88%D8%B1%D8%AA%D8%B1%D8%A7%D8%A8&diff=680883&oldid=680855
There was an unvisible character between ISBN and the number itself. I assume a non-joiner.