@article{ETNA_2005__20__a1,
     author = {Hochstenbach,  Michiel E.},
     title = {Generalizations of harmonic and refined {Rayleigh-Ritz}},
     journal = {Electronic transactions on numerical analysis},
     pages = {235--252},
     year = {2005},
     volume = {20},
     zbl = {1121.65316},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/ETNA_2005__20__a1/}
}