AF
Aḥmad Ibn Faḍlān
Ahmad ibn Fadlan ibn al-Abbas al-Baghdadi or simply known as Ibn Fadlan, was a 10th-century Arab traveler from Baghdad, Abbasid Caliphate, famous for his account of his travels as a member of an embassy of the Abbasid caliph al-Muqtadir to the king of the Volga Bulgars, known as his risāla.
Excerpt from Wikipedia, available under CC BY-SA 4.0.
Books

Ibn Fadlan and the Land of Darkness
2012
ISBN 9780140455076