The two published the music encyclopedia Musikkleksikon in 1949 .
Anker had also edited the general encyclopedia Nyco konversasjonsleksikon together with Rolf Haffner in 1935 .
The two published the music encyclopedia Musikkleksikon in 1949 , and Anker had also edited the general encyclopedia Nyco konversasjonsleksikon together with Rolf Haffner in 1935 .