The present document contains guidance for drafting a system reference document which is intended to be used initially for internal coordination within ETSI and subsequently@ in particular@ for co-operation with the Electronic Communications Committee (ECC) of the European Conference of Post and Telecommunications Administrations (CEPT)@ under the Memorandum of Understanding between ECC and ETSI. The present document is applicable to all ETSI Technical Bodies producing deliverables affecting radio frequencies.