Clothbound Tecla books
Consider getting the cloth edition. The cost isn't usually much more than paper, it is handsome, and the pages lie flat more easily.
They are usually in black with gold lettering on the spine. Most were bound for us in a small village in Hungary to a high standard, with good quality cloth, sewn not just pasted.
Here is what one guitar teacher wrote about Tecla clothbound books:
"I have greatly enjoyed the Sor volumes that I received from Tecla several months ago. Even though I have owned your previously published facsimile volumes for many years, I find myself going to the music much more now. With the cloth binding and clarity of the page and the fact that the page remains flat, it is a joy to read through. In fact, there is seldom a morning that I don't spend a few minutes playing through a short piece." (John Leonard, associate professor of classical guitar at Philadelphia for many years).
Librarians may also wish to get the cloth editions, because they are harder-wearing than paperbound.