Trace element analysis of maternal scalp hair by external beam proton-induced X-ray emission (PIXE) Hall, G.S.; Roach, N.; Simmons, U.; Cong, H.; Lee, M.I.; Cummings, E. Journal of Radioanalytical Chemistry 82(2): 329-339 1984 0134-0719 https://eurekamag.com/research/078/585/078585979.php