This was stated and proved without attribution in Burnside's 1897 textbook, but it had previously been discussed by Augustin Cauchy, in 1845, and by Georg Frobenius in 1887.
This proposition was stated and confirmed without attribution in Burnside's 1897 textbook, but it had been discussed earlier by Augustin Cauchy in 1845 and Georg Frobenius in 1887.