Reading
Talkin: A Robust Algorithm for Pitch Tracking (RAPT)
The classic algorithm for estimating F0 from speech signals.
Kawahara et al: Restructuring speech representations…
The key paper about the STRAIGHT vocoder, which was originally intended for manipulating recorded natural speech.
Taylor – Section 12.7 – Pitch and epoch detection
Only an outline of the main approaches, with little technical detail. Useful as a summary of why these tasks are harder than you might think.
Handbook of phonetic sciences – Ch 20 – Intro to Signal Processing for Speech
Written for a non-technical audience, this gently introduces some key concepts in speech signal processing.