@article{GDZPPN001172875, title = {A Theory for Nystr\"om Methods.}, journal = {Numerische Mathematik}, volume = {25}, year = {1975}, pages = {383-400}, zbl = {0307.65053}, url = {http://dml.mathdoc.fr/item/GDZPPN001172875} }
Hairer, E.; Wanner, G. A Theory for Nyström Methods.. Numerische Mathematik, Tome 25 (1975) pp. 383-400. http://gdmltest.u-ga.fr/item/GDZPPN001172875/