<xs:complexType name="_Service"> <xs:sequence> <xs:element ref="Name"/> <xs:element ref="Title"/> <xs:element minOccurs="0" ref="Abstract"/> <xs:element minOccurs="0" ref="KeywordList"/> <xs:element ref="OnlineResource"/> <xs:element minOccurs="0" ref="ContactInformation"/> <xs:element minOccurs="0" ref="Fees"/> <xs:element minOccurs="0" ref="AccessConstraints"/> </xs:sequence> </xs:complexType>