On Subplane Partitions of a Finite Projective Plane. - Peter Yff (J. Comb. Theory A, 1977)

On the Dénes-Hermann Theorem: a Different Approach. - Peter Yff (Eur. J. Comb., 1991)

Another Set of Concurrent Cevians: 10678. - Clark Kimberling; Peter Yff; Vasile Mihai (Am. Math. Mon., 2000)