Accourding To Richard Burton " The Isaak (Isaaq), Issas, Gadabuursi, And Barsuug Geneologies to Be Of Dir Origin, Aydur (Iidoor and Dirr)

 First footsteps in East Africaor, An Exploration of Harar Richard Burton 

https://burtoniana.org/books/1856-First%20Footsteps%20in%20East%20Africa/1856-FirstFootstepsVer2.htm

Richard Burton on Gadabuursi Issas Isaaq and Daarood origins

The old and pagan genealogies still known to the Somal, are Dirr, Aydur (Iidoor), Darud, and, according to some, Hawiyah. Dirr and Aydur (Iidoor), of whom nothing is certainly known but the name10, are the progenitors of the northern Somal, the Eesa, Gudabirsi, Ishak, and Bursuk tribes.