Articles about how to Compose an endgamestudy.
From the British Endgame Study News March 1996:
How I became a great composer, by Gady Costeff
source: http://gadycosteff.com/how_i_became_a_great_composer.pdf
(More about Chess Composition by Gady Costeff on: http://gadycosteff.com)
Compsing a study by John Nunn in The Problemist Jan 2019.
Source: https://www.wfcc.ch/wp-content/uploads/Nunn-Composing-a-Study-TP2019.pdf
STRIP OR MASSAGE? TWO WAYS OF CREATING STUDIES FROM GAMES
By Steffen Slumstrup Nielsen
Composing Endgame studies by Johan Hellsten at Chess.com
Source: https://www.chess.com/blog/jhellsten/composing-endgame-studies
Meine Schachkompositionen, by Gerhard Josten.
source: http://www.gerhard-josten.de/app/download/17252573/Schachkompositionen.pdf
(More about chess with Gerhard Josten on http://www.gerhard-josten.de/schach/)
From the (old) EBUR Promotion magazine an article (in Dutch) by Wouter Mees about how to compose:
From the (old) EBUR Promotion magazine an article (in Dutch) by Ignace Vandecasteele about how to compose a miniature.
Source (powerpoint): Lezing / Workshop Max Euwe Centrum 2012 (dutch) about "Chess studies composing with a computer".
Same in PDF: Workshop Van den Herik and Jan Timman 2012 see below.