Herstein 1975, стр. 26, §2. Herstein, Israel Nathan (1975), Topics in Algebra (2nd изд.), Lexington, Mass.: Xerox College Publishing, MR0356988.
Hall 1967, стр. 1, §1.1: "The idea of a group is one which pervades the whole of mathematics both pure and applied." Hall, G. G. (1967), Applied Group Theory, American Elsevier Publishing Co., Inc., New York, MR0219593, an elementary introduction.
Herstein 1975, стр. 26, §2. Herstein, Israel Nathan (1975), Topics in Algebra (2nd изд.), Lexington, Mass.: Xerox College Publishing, MR0356988.
Hall 1967, стр. 1, §1.1: "The idea of a group is one which pervades the whole of mathematics both pure and applied." Hall, G. G. (1967), Applied Group Theory, American Elsevier Publishing Co., Inc., New York, MR0219593, an elementary introduction.