@article {2962,
	title = {Nonlinear Component Analysis as a Kernel Eigenvalue Problem},
	journal = {Neural Computation},
	volume = {10},
	year = {1998},
	pages = {1299-1319},
	author = {Sch{\"o}lkopf, Bernhard and Smola, Alexander and M{\"u}ller, Klaus-Robert}
}
