John B. Fraleigh, A First Course in Abstract Algebra (7th ed.), Addison Wesley, 2002.
[2]
Thomas W. Judson, Abstract Algebra: Theory and Applications. Revised edition published under the GNU Free Documentation License, 1997 (revised 2016). http://abstract.pugetsound.edu/aata
[3]
Ivan Niven, Herbert S. Zuckerman, and Hugh L. Montgomery. An Introduction to the Theory of Numbers (5th ed.), John Wiley and Sons, 1991.