Inequalities Involving Altitudes and Exradii: 10759. - Calin Popescu; Achilleas Sinefakopoulos (Am. Math. Mon., 2000)

Problem 10804. - Achilleas Sinefakopoulos (Am. Math. Mon., 2000)

A Six Point Circle: 10710. - Bogdan Suceava; Achilleas Sinefakopoulos (Am. Math. Mon., 2000)

Cirumscribing an Inscribed Quadrilateral: 10804. - Achilleas Sinefakopoulos; Daniele Donini (Am. Math. Mon., 2001)

Problem 11014. - Achilleas Sinefakopoulos (Am. Math. Mon., 2003)

A Recursively Defined Series: 11014. - Achilleas Sinefakopoulos; Knut Dale (Am. Math. Mon., 2005)