\Bibitem{BiyDzh94} \by B.~N.~Biyarov, S.~A.~Dzhumabaev \paper A~criterion for the Volterra property of boundary value problems for Sturm--Liouville equations \jour Mat. Zametki \yr 1994 \vol 56 \issue 1 \pages 143--146 \mathnet{http://mi.mathnet.ru/mzm2233} \mathscinet{http://mathscinet.ams.org/mathscinet-getitem?mr=1309829} \zmath{https://zbmath.org/?q=an:0837.34035} \transl \jour Math. Notes \yr 1994 \vol 56 \issue 1 \pages 751--753 \crossref{https://doi.org/10.1007/BF02110567} \isi{https://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=Publons&SrcAuth=Publons_CEL&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=A1994RH68200016}