https://imslp.org/wiki/30_Sehr_leichte_%C3%BCbungsst%C3%BCcke%2C_Op.39_(Diabelli%2C_Anton)
http://ks.imslp.info/files/imglnks/usimg/3/35/IMSLP273463-PMLP443897-Diabelli_op39.pdf
https://www.youtube.com/playlist - Norbert Neunzling
https://www.youtube.com/playlist - Classical Guitar / Anton Diabelli - Uebungs Stücke- Op.39