Nguyen, Thieu Huy, et al. “Admissible Integral Manifolds for Partial Neutral Functional-Differential Equations”. Ukrains’kyi Matematychnyi Zhurnal, vol. 74, no. 10, Nov. 2022, pp. 1364-87, https://doi.org/10.37863/umzh.v74i10.6257.