A student recently came to me wondering what classical period repertoire he could work on the Wolf copy of a Grenser bassoon (circa 1800, at 430 HZ) other than concerti.
There are six beautiful duettinos by Franz Joseph Haydn and Christian Ludwig Dieter in an edition collected by William Waterhouse. These duets, published by Dieter at the end of 1806, derive from his various piano trios, string quartets, oratorios (The Creation), and his Symphony no. 99 and 100, as stated by Waterhouse.
Christian Dieter was known as a composer, violinist, flutist and bassoonist in Stuttgart. He was appointed the “Hofmusicus” and first violinist by the Duke of Württemberg in 1781. (https://en.wikipedia.org/wiki/Frederick_II_Eugene,_Duke_of_Württemberg)
Dieter also composed and published other sets of duets, two concertos and two concertos for two bassoons, which I have yet to find.
The 6 duettinos for two bassoons by Dieter and Haydn can be ordered from these links:
http://www.universaledition.com/sheet-music-and-more/6-duettinos-fuer-2-fagotte-haydn-joseph-/-dieter-christian-ludwig-ue18121?c=331
or:
http://www.jwpepper.com/7882947.item#.VhP5yHj0j8E