Print reference books are located either in the Reference Collection or in the general collection. (Large, multi-volume sets are often located in the general collection.)
The Encyclopaedia of Islam
Reference Collection: DS 37 .E523
E.J. Brill's First Encyclopaedia of Islam (9 vols.)
2nd Floor: DS 35.53 .E53 1987
Encyclopedia of Islam and the Muslim World (2 vols.)
Reference Collection: BP 40 .E525 2003
The New Encyclopedia of Islam
1st Floor: BP 40 .G42 2013
The Qurʼan: An Encyclopedia
Reference Collection: BP 133 .Q87 2006
Islamic Desk Reference
Reference Collection: DS 35.53 .I83 1994
The Muslim Almanac
1st Floor: BP 40 .M83 1996
The Oxford Encyclopedia of the Islamic World (6 vols.)