\Bibitem{GalPocShu24} \by V.~D.~Galkin, O.~V.~Pochinka, D.~D.~Shubin \paper Classification of non-singular four-dimensional flows with a non-twisted saddle orbit \jour Mat. Sb. \yr 2024 \vol 215 \issue 11 \pages 65--91 \mathnet{http://mi.mathnet.ru/sm10091} \crossref{https://doi.org/10.4213/sm10091}