Complex sentence: Empirical data on health locus of control in a number of fields was reviewed by Norman and Bennett in 1995; they note that data on whether certain health-related behaviors are related to internal health locus of control have been ambiguous.
Split into simpler sentences: Empirical data on health locus of control in various fields has been reviewed by Norman and Bennett (1995). These authors note that data on whether certain health-related behaviors are related to internal health locus of control have been ambiguous.