"The Bonner Durchmusterung [vols. 1-2] (Argelander 1859-62, Küstner 1903, Becker 1951, Schmidt 1968) is a visual survey of stars in the declination zones +89⁰ to -01⁰."
"The Southern Durchmusterung [vol. 3] (Schönfeld 1886, Becker 1949, Schmidt 1967) is a visual survey of stars in the declination zones - 02⁰ to -23⁰."