Fields with non-trivial Kaplansky's radical and finite square class number M. Kula — 1981 Acta Arithmetica
Quadratic Forms over Formally Real Fields with Eight Square Classes. M. Kula; L. Szczepanik; K. Szymiczek — 1979 Manuscripta mathematica
Quadratic form schemes and quaternionic schemes M. Kula; L. Szczepanik; Kazimierz Szymiczek — 1988 Fundamenta Mathematicae