Belorussian guitarist Tatyana Ryzhkova gives a nice lesson on melodic work, tremolo, and other warm-up exercises. This comes via her popular YouTube Channel. I haven’t been posting her lesson videos but this one is nice because the student can see more of a routine to how to practice the exercise rather than just the information needed. She mentions two books: Pumping Nylon by Scott Tennant and The Bible of Classical Guitar Technique (English version) by Hubert Käppel. He also has an english beginner method book which you can see via Amazon. In case you were about to ask, it looks like she’s using an ErgoPlay Tappert Classical Guitar Support.
Video Link & Source: https://youtu.be/WcXZ9kjJA-w