Following books on Auditing & Assurance are available over internet with certain licensing rules. Few books have limited preview permission.
Part A: Auditing & Assurance
Kumar, R. and Sharma, V. Auditing: principles and practice.
Tandon et. al. Practical Auditing.
Shinde, S. V. Practical Auditing.
Basu, S. K. Fundamentals of Auditing.
Basu, S. K. Auditing and Assurance.
Bagshaw, K. Audit and Assurance Essentials.
Gupta, S. Auditing.
Gupta, K. Contemporary Auditing.
ICAI. Standards on Quality Control for Firms that perform Audits.