This document specifies the neutron reference radiation fields, in the energy range from thermal up to 20 MeV, for calibrating neutron-measuring devices used for radiation protection purposes and for determining their response as a function of neutron energy. This document is concerned only with the methods of producing and characterizing the neutron reference radiation fields. The neutron reference radiation fields specified are the following: — neutron fields from radionuclide sources, including neutron fields from sources in a moderator; — neutron fields produced by nuclear reactions with charged particles from accelerators; — neutron fields from reactors.