event-type attribute must be on allowed list of event types ("received" "revised" "accepted" "xml-converted" "xml-created" "digitized" "accepted-manuscript" "ahead-of-issue" "build-issue-online" "final" "tagger" "corrected" "retracted" "provenance")
date must be present within event
date must have an actual date tagged in year, month and day.
At least one pub-history event should be included with event-type "tagger" and a description in event-desc.
XML that has been converted from existing XML or other digital source materials should have a pub-history event with event-type "xml-converted"
XML created from PDF or scanned physical materials should have a pub-history event with event-type "digitized"
A description should be provided in event-desc for an event with event-type "tagger", "xml-created", "xml-converted", "digitized", or "provenance"
year should be represented by a 4 digit number, "." is not a valid year.