Habison, Peter (1998). «Astrometry and early astrophysics at Kuffner Observatory in the late 19th century». Acta Historica Astronomiae3: 93–94. ISSN0003-2670. Bibcode: 1998AcHA....3...93H.
Habison, Peter (1998). «Astrometry and early astrophysics at Kuffner Observatory in the late 19th century». Acta Historica Astronomiae3: 93–94. ISSN0003-2670. Bibcode: 1998AcHA....3...93H.