found: Mitton, J. Cambridge dict. of astreonomy, 2001(Comet Biela (3D/Biela))
found: Dict. of astronomy, 2003(Bield, Comet 3D: a now disintegrated periodic comet)
found: Firefly astronomy dict., 2003(Biela's Comet: a now disintegrated comet of period 6.62 years)
found: Darling, D. Universal book of astronomy, 2004(Biela's comet, periodic comet, broke up on its 1846 return)
found: Kronk, G.W. Comets : a descriptive catalog, 1984:p. 222 (Biela, discovered Mar. 8, 1772)
found: Brandt, J.C. Introduction to comets, 2004:p. 271 ("Comet Biela in the 19th century provided an example of a comet splitting and possible complexities. The comet was seen in 1832 and had a period of about 6.6 years. The 1839 apparition was not favorable. [...] At the 1846 apparition, Biela's Comet returned as two comets, close together on the sky, each with a tail. [...] Similar behavior was seen in the 1852 apparition except that the two comets were about 2 million kilometers apart. On the next pass in 1859, the observing conditions were poor. But, the observing conditions in 1866 were excellent and the comet was not observed. Comet Biela was never seen again.")
