  Diogenes Laertius lists a large number of works by Democritus on many fields, including ethics, physics, mathematics, music and cosmology.  Two works, the Great World System and the Little World System (see the entry on    doxography of ancient philosophy),  are sometimes ascribed to Democritus, although Theophrastus reports that the former is by Leucippus (DK 68A33).  There is more uncertainty concerning the authenticity of the reports of Democritus' ethical sayings.  Two collections of sayings are recorded in the fifth-century anthology of Stobaeus, one ascribed to Democritus and another ascribed to an otherwise unknown philosopher ‘Democrates’.  DK accepts both as relating to Democritus, but the authenticity of sayings in both collections is a matter of scholarly discussion, as is the relationship between Democritus' atomism and his ethics.