Stephen Harrison is the name of at least two authors:
1)
Stephen Harrison (1947-), author of
Controlling Health Professionals2)
S. J. Harrison (1960-), classicist and editor of
A Companion to Latin LiteratureEmanational Physics and
Jordan's Catch are likely to be by further authors.
4.
Stephen Harrison (1954-), author of
Power Crystals 
Combination issues