Source: https://www.researchgate.net/profile/Samuel-Pare-2/publication/230734747_Etude_d'une_argile_locale_du_Burkina_Faso_a_des_fins_de_decontamination_en_Cu2_Pb2_et_Cr3/links/09e41503b668b96e1c000000/Etude-dune-argile-locale-du-Burkina-Faso-a-des-fins-de-decontamination-en-Cu2-Pb2-et-Cr3.pdf