1.
Kuzhel’ SA, Patsyuk OM. On the theory of $\mathcal{PT}$-symmetric operatorss. Ukr. Mat. Zhurn. [Internet]. 2012Jan.25 [cited 2024Mar.28];64(1):32-9. Available from: https://umj.imath.kiev.ua/index.php/umj/article/view/2554