@article{10_4064_sm_70_1_1_9,
     author = {Andrzej Pokrzywa},
     title = {Method of orthogonal projections and approximation of the spectrum of a bounded operator {II}},
     journal = {Studia Mathematica},
     pages = {1--9},
     publisher = {mathdoc},
     volume = {70},
     number = {1},
     year = {1981},
     doi = {10.4064/sm-70-1-1-9},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.4064/sm-70-1-1-9/}
}