Bosworth, C.E.. History of Civilizations of Central Asia (en). UNESCO, 1 January 1998 — 164-bet. ISBN 978-92-3-103467-1. „This dynasty eventually built up, as the Seljuq empire in the east tottered to its close, the most powerful and aggressively expansionist empire in the Persian lands, in the end defeating their rivals for control of Khurasan, the Ghurids of Afghanistan, threatening western Persia and Iraq and the Abbasid caliphate itself, and only disintegrating under the overwhelming military might of the Mongol invaders in the opening decades of the thirteenth century.“
