Gillian Barker received Ph.D. from Bristol University, England, where she has also served as a visiting professor in the Department of the History of Art. Central to her research interests is the Islamic garden, including the Norman Palace of La Zisa in Palermo, Sicily. 

Sources:

"ArchNet Sites," Archnet.org.http://archnet.org/archive/message_36855
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Gillian Barker