@article {jackson2016effects,
title = {Effects of heavy alkali elements in Cu (In, Ga) Se2 solar cells with efficiencies up to 22.6\%},
journal = {physica status solidi (RRL){\textendash}Rapid Research Letters},
volume = {10},
year = {2016},
pages = {583{\textendash}586},
author = {Jackson, Philip and Wuerz, Roland and Hariskos, Dimitrios and Lotter, Erwin and Witte, Wolfram and Powalla, Michael}
}
@article {powalla2013high,
title = {High-efficiency Cu(In,Ga)Se2 cells and modules},
journal = {Solar energy materials and solar cells},
volume = {119},
year = {2013},
pages = {51{\textendash}58},
author = {Powalla, Michael and Jackson, Philip and Witte, Wolfram and Hariskos, Dimitrios and Paetel, Stefan and Tschamber, Carsten and Wischmann, Wiltraud}
}