<schema xmlns=“www.ascc.net/xml/schematron” >
<pattern name="Number of characters in an abbreviation"> <rule context="BBB"> <report test="string-length(@bbb) < 2">There is not enough letters in the abbreviation</report> <report test="string-length(@bbb) > 3">There is too much letters in the abbreviation</report> </rule> </pattern>
</schema>