The Value of Primitive Words: 10636. - David Callan; Robin J. Chapman; John H. Lindsey II; Danrun Huang (Am. Math. Mon., 2000)

Problem 11052. - Danrun Huang; Daniel Scully (Am. Math. Mon., 2003)

The Limit of a Set-Valued Process: 11052. - Danrun Huang; Daniel Scully; Achava Nakhash; Karl David (Am. Math. Mon., 2006)