Text may contain numeric and named character entities . Specifies a group. Both A and B are permitted in any order. A few HTML elements use an additional SGML feature to exclude certain elements from content model. Excluded elements are preceded by a hyphen.
Explicit exclusions override inclusions.
It is followed by the name of the element in question and a list of attribute definitions. The name of an attribute. The type of the attribute's value or an explicit set of possible values. Values defined explicitly by the DTD are case-insensitive. Some attributes explicitly specify a default value for the attribute.