books.google.com - This book is an undergraduate textbook on abstract algebra, beginning with the theories of rings and groups. As this is the first really abstract material students need, the pace here is gentle, and the basic concepts of subring, homomorphism, ideal, etc are developed in detail. Later, as students gain...https://books.google.com/books/about/Introduction_to_Algebra.html?id=syYYl-NVM5IC&utm_source=gb-gplus-shareIntroduction to Algebra