@article {cordero2013groupwise, title = {Groupwise elastic registration by a new sparsity-promoting metric: application to the alignment of cardiac magnetic resonance perfusion images}, journal = {Pattern Analysis and Machine Intelligence, IEEE Transactions on}, volume = {35}, number = {11}, year = {2013}, pages = {2638{\textendash}2650}, publisher = {IEEE}, author = {Lucilio Cordero-Grande and S. Merino-Caviedes and Santiago Aja-Fern{\'a}ndez and Carlos Alberola-Lopez} }