A Quartic (H. Holloway and M. S. Klamkin). - Stanley Rabinowitz (SIAM Rev., 1994)

Problem 11213. - Stanley Rabinowitz (Am. Math. Mon., 2006)

One from 1995: 10483. - Stanley Rabinowitz; Roberto Tauraso (Am. Math. Mon., 2006)

Sometimes an Integer: 11213. - Stanley Rabinowitz; et al. (Am. Math. Mon., 2008)