This is a bit of grabbing at straws, since WorldCat doesn't show the original publication of this, but there are 2 sonatinas for clarinet and piano by Richard Hofmann, and the original publisher was C.F.W. Siegel. (Not the newer republished edition by FEJA Musikverlag from 1994.) If anyone happens to have the original Siegel edition to upload, I would be most appreciative!
[edit]: The International Clarinet Association has both sonatinas in their archive at the University of Maryland, if anyone would be willing to borrow, scan, and upload.