Author,Title,Edition,Publisher,Year,Series,Number,ISBN,ISSN,URL
"Duggal, Krishan L. and Bejancu, Aurel",Lightlike submanifolds of semi-Riemannian manifolds and applications,,Kluwer Academic,1996,Mathematics and its applications,,0792339576,,https://cir.nii.ac.jp/crid/1130000793742730880