\Bibitem{Gur79} \by D.~I.~Gurevich \paper Generalized displacement operators with a~right infinitesimal Sturm--Liouville operator \jour Mat. Zametki \yr 1979 \vol 25 \issue 3 \pages 393--408 \mathnet{http://mi.mathnet.ru/mzm8316} \mathscinet{http://mathscinet.ams.org/mathscinet-getitem?mr=534095} \zmath{https://zbmath.org/?q=an:0452.47058} \transl \jour Math. Notes \yr 1979 \vol 25 \issue 3 \pages 208--215 \crossref{https://doi.org/10.1007/BF01159513}