Dennis Davenport
www.math.buffalo.edu/mad/PEEPS/davenport_dennisE.html
3 Aug 2011:
Research Notes. Dennis Davenport; Neil Hindman, A proof of van Douwen's right ideal theorem, Proc. ... Dennis Davenport; Neil Hindman, Subprincipal closed ideals in $beta N$, Semigroup Forum 36 (1987), 223--245.