Sor’s second set of studies for the guitar, op. 29, was published in Paris in 1827 shortly after his return from Russia where it is likely that they were composed.
The studies op. 29 nos. 20 and 21 are FREE TO EVERYBODY. Op. 29 no. 20 is particularly interesting because of the sonority of the piece if you follow Sor’s instructions – try it, it can be a fine result!
This edition comes from the new 2020 second edition of Sor’s New Complete Works for Guitar edited by Brian Jeffery. The Introduction and Index to the entire series can be seen here on this site.