@article{ETNA_2013__40__a3,
     author = {Mach, Thomas and Prani\'c, Miroslav S. and Vandebril, Raf},
     title = {Computing approximate extended {Krylov} subspaces without explicit inversion},
     journal = {Electronic transactions on numerical analysis},
     pages = {414--435},
     publisher = {mathdoc},
     volume = {40},
     year = {2013},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/ETNA_2013__40__a3/}
}