Johann Christoph Kellner (1736-1830) is the son of Johann Peter Kellner, who was a Bach's pupil.
He wrote music in a simple and attractive galant style, as it's the case for this Quartetto which, as far as I could check, is new on CCH.
Kellner has composed the Quartetto for two organists. After playing it 4 hands with a friend, it was a true disappointment not to have the possibility to play it alone. So I tried to adapt it so that it would be playable by an organist alone, while trying not to betray the original too much.