1. Éléments de mathématique, XIV, Part 1, Les structures fondamentales de l'analyse, Livre II: Algèbre,;Bourbaki,1952
2. A note on the preceding paper (Walsh [15]);Curtiss;Trans. Amer. Math. Soc.,1922
3. On the zeros of a polynomial;Grace,1900
4. Functional Analysis and Semigroups;Hille,1957
5. On a theorem of Grace;Hörmander;Math. Scand.,1954