+@article{Hestenes52,
+ author = {Hestenes, M. R. and Stiefel, E.},
+ journal = {Journal of research of the National Bureau of Standards},
+ pages = {409--436},
+ timestamp = {2008-10-07T16:03:39.000+0200},
+ title = {Methods of conjugate gradients for solving linear systems},
+ volume = {49},
+ year = {1952}
+}
+