ded:Definition: An element of format that specifies the MIME type for the
resource being described. The Internet Media Type [MIME] of the Resource. See
IRM Spec Category: Format.
ded:Obligation: (Conditional) Mandatory if format is present.
ded:Comment: mimeType is expressed as: category/specific-type, such as
?image/gif?. A comprehensive list of existing MIME types is available on the
Internet at http://www.iana.org/assignments/media-types/.