Daniel E. Wulbert, The Rational Approximation of Real Functions, American Journal of Mathematics, Vol. 100, No. 6 (Dec., 1978), pp. 1281-1315 ...

We prove two results with regard to rational inner functions in the Schur-Agier class of the tridisk. Every rational inner function of degree (n, 1,1) is in the Schur-Agier class, and every rational ...