Douglas has directed 23 Ph. D students , some of whom became renowned mathematicians .
Douglas ' book Banach Algebra Techniques in Operator Theory in the series Graduate Texts in Mathematics is one of the classics in operator theory .
Douglas has directed 23 Ph. D students , some of whom became renowned mathematicians , and his book Banach Algebra Techniques in Operator Theory in the series Graduate Texts in Mathematics is one of the classics in operator theory .