\Bibitem{GelShm83} \by I.~M.~Gel'fand, G.~S.~Shmelev \paper Geometric structures of double bundles and their relation to certain problems in integral geometry \jour Funktsional. Anal. i Prilozhen. \yr 1983 \vol 17 \issue 2 \pages 7--22 \mathnet{http://mi.mathnet.ru/faa1530} \mathscinet{http://mathscinet.ams.org/mathscinet-getitem?mr=705042} \zmath{https://zbmath.org/?q=an:0519.53058|0535.53055} \transl \jour Funct. Anal. Appl. \yr 1983 \vol 17 \issue 2 \pages 84--96 \crossref{https://doi.org/10.1007/BF01083134} \isi{https://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=Publons&SrcAuth=Publons_CEL&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=A1983RW64900021}