Source: https://www.researchgate.net/profile/Abdelhakim-Chillali/publication/322812987_Proceedings_of_International_Conference_on_Applied_Mathematics_ICAM'_2017_Taza_Morocco_October_19-20_2017_Editorial/links/5a7a21de45851541ce5e71f3/Proceedings-of-International-Conference-on-Applied-Mathematics-ICAM-2017-Taza-Morocco-October-19-20-2017-Editorial.pdf