Fix for broken URL: removed note pointing to ISO 12620 document on ISOCat site, since 
that page is now gone and ISOCat seems to be winding down; added a URL for the ISO 12620
document on the ISO site to the relevant bibliography item instead.


git-svn-id: svn+ssh://svn.code.sf.net/p/tei/code/trunk@13091 e5332ce4-a50f-0410-b94b-d658400b0204