Problem 10781. - Leonard Smiley (Am. Math. Mon., 2000)

A Rational Generating Function for Relative Divisors: 10750. - Leonard Smiley; David Callan; David M. Wells; Saïd Amghibech (Am. Math. Mon., 2001)

A Tree-Counting Identity: 10781. - Leonard Smiley; Helmut Prodinger; Robin Chapman; et al. (Am. Math. Mon., 2002)