1. A Collection of Mathematical Problems;Ulam,1960
2. On the Stability of the Linear Functional Equation
3. Ulam Stability of Operators;Brzdek,2018
4. Hyers-Ulam Stability of Ordinary Differential Equations;Tripathy,2021
5. Hyers stability of the linear differential equation;Obloza;Rocznik Nauk-Dydakt. Prace Mat.,1993