I'm very glad tath I helped .
The most full and thorough edition I could tink of is "Catalogue of Bulgarian post stamps 1879-2019",published in 2019 by Sofia Philatelical Society " Petko B.Caraivanov ". It sales, for 52 dollars and gives actual information and prices in leva ,about the different issues . Unfortunately it's not translated to English language.
I'm posting samples of it to look .