%0 Book %T Indefinite Inner Product Spaces %A J. Bognar %D 1974 %I Springer-Verlag %C New York %F Bognar1974 %0 Journal Article %T Linear mappings approximately preserving orthogonality %A J. Chmielinski %J J. Math. Anal. Appl. %D 2005 %V 304 %F Chmielinski2005 %0 Book %T Indefinite Linear Algebra and Applications %A I. Gohberg %A P. Lancaster %A L. Rodman %D 2005 %I Birkhauser Verlag %C Basel %F Gohberg2005 %0 Journal Article %T Orthogonality Preserving Mappings in Krein Spaces %A A. Saraei %A M. Amyari %J J. Math. Anal. %D 2019 %V 10 %F Saraei2019 %0 Journal Article %T Approximately orthogonality preserving maps in Krein spaces %A A. Saraei %A M. Amyari %J Aequationes Math. %D 2020 %V 94 %F Saraei2020 %0 Journal Article %T Operators preserving sesquilinear form %A P. Wojcik %J Linear Algebra Appl. %D 2015 %V 469 %F Wojcik2015