Nirmalkumar, R., and R. Murugesu. “Approximate Controllability Results for Second Order Neutral Impulsive Stochastic Evolution Equations of Sobolev Type With Unbounded Delay”. Journal of Applied Nonlinear Dynamics, vol. 8, no. 2, Aug. 2026, pp. 291-04, https://doi.org/10.5890/JAND.2019.06.011.