Quadrilaterals in an Isosceles Triangle: 10653. - Marcin Mazur; Roy Barbara; Jean Anglesio; Robin J. Chapman; N. Lakshmanan; John Melville; G. Peng; C. R. Pranesachar (Am. Math. Mon., 2000)

When ABC Is Equilateral: 10838. - Florian S. Pârvânescu; Roy Barbara (Am. Math. Mon., 2002)

A Sum Related to Quadratic Residues: 10852. - Calin Popescu; Roy Barbara; Omran Kouba (Am. Math. Mon., 2002)