Recommended reading (any of the following):
• James Ward Brown & Ruel V. Churchill, Complex variables and Applications, 8th ed., McGraw-Hill, 2009.
• Erwin Kreyszig, Advanced engineering mathematics, 8th ed., John Wiley & Sons, 1999 (or other edition).
• Jerrold E. Marsden & Michael J. Homan, Basic complex analysis, 2nd ed., W.H. Freeman & Co, New York, 1987.