1. U.S. Geological Survey (2013) Mineral commodity summaries. Available at
http://minerals.usgs.gov/minerals/pubs/mcs/2013/mcs2013.pdf
2. Russell R, Tous L, Philipsen H, Horzel J, Cornagliotti E, Ngamo M, Choulat P, Labie R, Beckers J, Bertens J, Fujii M, John J, Poortmans J, Mertens R (2012) A simple copper metallization process for high cell efficiencies and reliable modules. In: Proceedings of the 27th European photovoltaic solar energy conference and exhibition, Frankfurt, pp 538–543
3. U.S. Geological Survey (2013) 2011 Minerals yearbook. Available at
http://minerals.usgs.gov/minerals/pubs/commodity/myb/
4. Kessler M, Munster D, Neubert T, Mader CP, Schmidt J, Brendel R (2011) High-efficiency back-junction silicon solar cell with an in-line evaporated aluminum front grid. In: Conference record of the 37th IEEE photovoltaic specialists conference, Seattle, pp 1085–1090
5. Sarti D, Einhaus R (2002) Silicon feedstock for the multi-crystalline photovoltaic industry. Sol Energy Mater Sol Cells 72:27–40