@incollection{NIPS2005_643,
 title = {Spectral Bounds for Sparse PCA: Exact and Greedy Algorithms},
 author = {Baback Moghaddam and Yair Weiss and Shai Avidan},
 booktitle = {Advances in Neural Information Processing Systems 18},
 editor = {Y. Weiss and B. Sch\"{o}lkopf and J. Platt},
 publisher = {MIT Press},
 address = {Cambridge, MA},
 pages = {915--922},
 year = {2006}
}