The Arithmetical Theory of Linear Recurring Series
Morgan Ward · Transactions of the American Mathematical Society · 1933
k -2, and the author, these Transactions, vol.33 (1931), pp.153-165, the case £ = 3.For general k, see R. D. Carmichael, Quarterly Journal of Mathematics, vol.48 (1920), pp.343-372.Certain of Carmichael's results were extended by the use of ideals by H. T. Engstrom, these Transactions, vol.33 (1931), pp.210-218.1 shall refer to these papers by the authors' name and page number.For the bearing of the problem upon elementary number theory, see R. T>.Carmichael, American