Function pm#publish_date__publishdate (? -> entity)
supertype: Date (? -> entity) to specify a date associated with an event in the life cycle of a resource; in WebKB, pm#time or other MORE PRECISE RELATIONS SHOULD BE USED INSTEAD
supertype: attributive_relation__attributiverelation (*) like pm#binary_relation, this type mostly exists to categorize what cannot be categorized elsewhere
supertype: relation_playing_a_special_role (*) this type permits to categorize relations according to their roles ; this is a traditional but quite subjective way of categorizing relations
>part of: relation__related_thing__relatedthing___related_with type for any relation (unary, binary, ..., *-ary) and instance of pm#relation_type