Source: https://www.researchgate.net/profile/Andre-Michard/publication/258531129_Nouveaux_guides_geologiques_et_miniers_du_MarocNew_Geological_and_Mining_Guidebooks_of_Morocco_volume_6_Anti-Atlas_occidental_et_Provinces_sahariennes/links/00b7d5289e337b258c000000/Nouveaux-guides-geologiques-et-miniers-du-Maroc-New-Geological-and-Mining-Guidebooks-of-Morocco-volume-6-Anti-Atlas-occidental-et-Provinces-sahariennes.pdf