I would like to thank Roberto Stelling, Panagis Sklavounos, Anders Mattsson, Valentin Albillo, Glenn Rhoads, Andrej Jakobcic, Christophe Prechac, Cornel Pacurar, Kevin Begley, Vishal Mehta , Mark Needleman and many others, who have provided valuable suggestions, corrections and encouragement for the improvement of this page. The excellent books of Triantafyllos Siaperas 'The Chess' Volumes 1&2 contain some of the board positions and problems presented in this page and gave ideas for many more. Retrograde analysis problems have been published by R. Smullyan in the brilliant books 'The Chess Mysteries of the Arabian Knights' and 'The Chess Mysteries of Sherlock Holmes'. Other great books which have been consulted or have contributed to this page are: 'The Usborne book of Chess Puzzles' by D. Norwood (very well-designed colourful introductory book), 'Classic Chess Problems' by K.S.Howard, 'Combination Art' by M. Bloh, and 'Pick of the Best Chess Problems' compiled by B. P. Barnes. The Chess-l has always been a valuable source of information and some of the problems of these pages have originally appeared and discussed in the list. I'd like to especially mention Thomas Hall and his series of articles titled "Beauty of Chess". Also, some of the problems here, have been 'fished' from the chess columns of the Greek Newspapers "Eleftherotypia" and "Ta Nea". Some of the graphics of this page have been designed by George Milakis.