Extensions of the D(∓k 2)-triples {k 2, k 2 ± 1, 4k 2 ± 1}. - Yasutsugu Fujita (Period. Math. Hung., 2009)

The extension of the D(-k 2)-pair {k 2, k 2 + 1}. - Yasutsugu Fujita; Alain Togbé (Period. Math. Hung., 2012)

Diophantine triples with largest two elements in common. - Mihai Cipu; Andrej Dujella; Yasutsugu Fujita (Period. Math. Hung., 2021)

The extension of the D(-k)-pair k, k+1 to a quadruple. - Nikola Adzaga; Alan Filipin; Yasutsugu Fujita (Period. Math. Hung., 2022)

Extensions of a Diophantine triple by adjoining smaller elements II. - Mihai Cipu; Andrej Dujella; Yasutsugu Fujita (Period. Math. Hung., 2024)

Contributions to Ma's conjecture concerning abelian difference sets with multiplier -1 (I). - Yasutsugu Fujita; Maohua Le (J. Comb. Theory, Ser. A, 2025)