Statistiske Undersøgelser angaaende Aandssvage i Danmark 1888-1889, = Statistical investigations concerning the imbeciles (idiots and feeble-minded) in Denmark 1888-1889 /
Carlsen, Johan Nils Gottlob.
Kjøbenhavn & London,
1891.
Abridged English translation by C.F. Nielsen.
Denmark Copenhagen.