APA
Ridley J. E., . (1997). Introduction to programmable logic controllers. London: Arnold.
Chicago
Ridley J E, . 1997. Introduction to programmable logic controllers. London: Arnold.
Harvard
Ridley J. E., . (1997). Introduction to programmable logic controllers. London: Arnold.
MLA
Ridley J E, . Introduction to programmable logic controllers. London: Arnold. 1997.