He has co-authored the standard text on calendrical calculations,
Calendrical Calculations, with
Nachum Dershowitz. In 1981 he was the co-author, with
John Tilford, of the canonical paper "Tidier Drawings of Trees" which described a method, now known as the
Reingold-Tilford algorithm, to produce more aesthetically pleasing drawing of binary (and by extension, m-ary) trees . ==References==