Hello FAUVETTE the first link DISCOGS relates the information on the musician composer and lists the songs which were described by the subscribers of the site. The title is thus rare and was not mentioned;
On the other hand the important thing was to know that the majority of the titles were managed for the questions of rights by the GEMA.DE in Germany.
It is thus well in the catalog (second link) of the GEMA that all the names of the rights holders were discovered, as well as the name of the publisher. On the other hand I do not have the postal or e-mail address of the publisher ...it is necessary to ask it to the GEMA.DE which should give the information. Problem ... it seems to date and nothing says that the publisher still exists. In this case this approach of German sites for the partitions.