Try Chemical Separations and Measurements, by Peters, Hayes, and Hieftje, Page 379. Its an older manual.

Usually, you have titration points (a volume of titrant and mv, if working potentiometrically). My analytical professor said (many, many years ago) that the first derivative plot will identify the titration point nearest the end point.

The second derivative allows mathmatical interpolation between titration points. Supposedly, the second derivative is more accurate, giving a more precise volume of titrant.