NUMERICAL ANALYSIS AND COMPUTATIONAL PROCEDURES - S. A. MOLLAH.
Numerical Methods: For Scientific and Engineering Computation - Jain Iyenger Jain.
Introductory Methods of Numerical Analysis - S.S. Sastri.
Introduction to Numerical Analysis: Second Edition (Dover Books on Mathematics) - F. B. Hildebrand
An Introduction to Numerical Analysis - Kendall Atkinson
Buy books instead of downloading them online. It's a good investment.
You can download some books online without paying anything. This is, in most cases, illegal due to copyright infringement. Do this at your own risk. We always recommend that you buy the ebook or the printed version. But we inform our readers about some of those illegal websites just for knowledge. We again warn you that downloading books is illegal in most cases. For more information, google it.
Library Genesis [sometimes goes down, visit their Wikipedia page for the current working URL]
Z-Library [may go down or the URL may change, visit their Wikipedia page].