@article{AFM_1980_5_2_a9,
     author = {Pekka Sorjonen},
     title = {Extensions of isometric and symmetric linear relations in a {Krein} space},
     journal = {Annales Fennici Mathematici},
     pages = {355--375},
     publisher = {mathdoc},
     volume = {5},
     number = {2},
     year = {1980},
     doi = {10.5186/aasfm.1980.0524},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.5186/aasfm.1980.0524/}
}