Fundamental solution E n of the operator ∂ 2 / ∂ t 2 - Δ n for n>3 Zofia Szmydt, Bogdan Ziemian (1979) Annales Polonici Mathematici
Fundamental solution for operators preserving a quadratic form Zofia Szmydt, Bogdan Ziemian (1983) Annales Polonici Mathematici
Fundamental solutions of the differential operator ( - 1 ) n D 1 n D 2 n + a ( i D 1 ) n + b ( i D 2 ) n + c Věra Radochová (1980) Časopis pro pěstování matematiky