Message
pub-date[@publication-format="electronic"] must have an actual date tagged in year, month and day.
Rule XPath:
This rule ASSERTS the following, raising an alert if FALSE:
(every $item in (year, month, day) satisfies $item castable as xs:integer) and string-join((year[string-length(.)
eq 4], format-number(month, '00'), format-number(day, '00')), '-') castable as xs:date
or not(ancestor::article-meta)