Dufresne Jean. Sammlung leichterer Schachaufgaben Tom II

Malmö: Electronic Edition, 2003. — 133 p.
This edition is based on the printed edition published by Philipp Reclam jun., Leipzig in 1882.
All direct problems and selfmates have been computer tested using Matthieu Leschemelle’s computer program Problemiste. The studies have been manually tested using Fritz 6 with the Nalimov endgame database. The conditional problems, however, have only been checked for obvious errors