For further papers of Robert Willis see MSS Add. 5022-5045, 5058-5062, 5064, 5071, 5074, 5075 and 5078-5082. The Library also holds a collection of papers of Willis' collaborator, John Willis Clark, parts of which are either by Willis or concern him and and his work. See MSS.Add.5063, 5065-5070, 5072, 5073, 5076, 5077, 5083, 5091 and 5103. Cambridge University Library holds a catalogue by Willis of writers on music and sound, MS.Add.4307.