<xs:complexType name="interval"><xs:annotation><xs:documentation>Represents an interval via a lower bound and an upper bound.</xs:documentation></xs:annotation><xs:sequence><xs:element name="description" type="xmcda:description" minOccurs="0"/><!-- At least one among (lowerBound, upperBound), or both --><xs:choice><xs:sequence><xs:element name="lowerBound" type="xmcda:value"/><xs:element name="upperBound" type="xmcda:value" minOccurs="0"/></xs:sequence><xs:element name="upperBound" type="xmcda:value"/></xs:choice></xs:sequence></xs:complexType>