@conference {Petra-et-al-08b,
	title = {Enhancing Sparsity by Constraining Strategies: Constrained SIRT versus Spectral Projected Gradient Methods},
	booktitle = {Proc. 7th Workshop on Modelling of Environmental and Life Sciences Problems (WMM 08)},
	series = {Ed Acad Romane},
	year = {2008},
	address = {Bucharest, Romania},
	author = {Petra, S. and Popa, C. and Schn{\"o}rr, C.}
}
