Yes; works of Sigfrid Karg-Elert are in the public domain.
Sigfrid Siwertz's birth name is Per Sigfrid Siwertz.
Sigfrid Öberg was born in 1907.
Sigfrid Öberg died in 1949.
Sigfrid Mohn was born in 1930.
Sigfrid Lundberg died in 1979.
Sigfrid Lindberg was born in 1897.
Sigfrid Lindberg died in 1977.
Sigfrid Edström was born on November 21, 1870.
Sigfrid Lundberg was born on 1895-02-15.
Sigfrid Siwertz died on November 26, 1970.
Sigfrid Henrici died on 1964-11-08.
Sigfrid Karg-Elert died in 1933.