@article{AFM_1969_421-450_a20,
     author = {Juhani Tienari},
     title = {Deficiency indices of linear mapping},
     journal = {Annales Fennici Mathematici},
     publisher = {mathdoc},
     volume = {421-450},
     year = {1969},
     doi = {10.5186/aasfm.1969.430},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.5186/aasfm.1969.430/}
}