Relation sumo#refers (?,?)  the 1st argument mentions or includes a reference to the 2nd argument, e.g., an article whose topic is a recent change in the price of oil may refer to many other things, e.g., the general state of the economy, the weather in California, the prospect of global warming, the options for alternative energy sources, the stock prices of various oil companies, etc.
  supertype:  Relation (pm)  to specify a reference to a related resource; in WebKB, pm#relation or MORE PRECISE RELATION TYPES SHOULD BE USED INSTEAD
  instance of:  binary_predicate_type (pm)
  subtype:  names__name (string,?)  the string names the 2nd argument
     subtype:  unique_identifier (string,?)  the string uniquely identifies the 2nd argument
  subtype:  represents (?,?)  the 1st argument in some way indicates, expresses, connotes, pictures, describes ... the 2nd argument
     subtype:  contains_information (content_bearing_object,proposition)  relates a content_bearing_object to the proposition it expresses; examples include the relationships between a physical novel and its story and between a printed score and its musical content
     subtype:  realization (?,?)
  subtype:  see_also__seealso (?,entity)
     subtype:  is_defined_by (?,entity)  in WebKB, pm#definition SHOULD BE USED INSTEAD
        subtype:  definition (?,description_content/medium/container)  see also #definition
           subtype:  definition (description_content/medium/container,description_content/medium/container)  a logical relation should be used instead of this relation
     subtype:  imports__import (?,entity)  if imports(X,Y) and you believe X, then you should believe what is in Y