\Bibitem{Mey38} \by N.~Meymann \paper Sur les polyn\^omes R-prolongeables \jour Sb. Math. \yr 1938 \vol 45 \issue 3 \mathnet{http://mi.mathnet.ru//eng/sm5726} \zmath{https://zbmath.org/?q=an:0019.24502|66.1200.02|64.1506.01}