doi:10.1016/0550-3213(87)90253-7engde Wit, BernardNicolai, Hermann CThe consistency of the S$^{7}$ truncation in d = 11 supergravityGeneral Theoretical PhysicsCERN-TH-4359-861987http://cds.cern.ch/record/16888310.1016/0550-3213(87)90253-7http://cds.cern.ch/record/168883oai:cds.cern.ch:168883