Perpendicularity in an Abelian Group. - Pentti Haukkanen; Mika Mattila; Jorma K. Merikoski; Timo Tossavainen (Int. J. Math. Math. Sci., 2013)

On the positive definiteness and eigenvalues of meet and join matrices. - Mika Mattila; Pentti Haukkanen (Discret. Math., 2014)

Studying the singularity of LCM-type matrices via semilattice structures and their Möbius functions. - Pentti Haukkanen; Mika Mattila; Jori Mäntysalo (J. Comb. Theory A, 2015)

The Arithmetic Jacobian Matrix and Determinant. - Pentti Haukkanen; Jorma K. Merikoski; Mika Mattila; Timo Tossavainen (J. Integer Seq., 2017)

Studying the inertias of LCM matrices and revisiting the Bourque-Ligh conjecture. - Pentti Haukkanen; Mika Mattila; Jori Mäntysalo (J. Comb. Theory A, 2020)