Acarnley, P. P. <br/><br/>
Stepping motors :  a guide to modern theory and practice / 
P.P. Acarnley. 
 - Rev. 2nd ed. 
 - London, U.K. :  P. Peregrinus on behalf of the Institution of Electrical Engineers,  1984, c1982. 
 - viii, 160 p. :  ill. ;  23 cm. 
 - IEE control engineering series ;  19 .