ebrary, Inc, & Melark, P. G. (2012). Comets: Characteristics, composition and orbits. Nova Science Publishers.
Chicago-viite (17. p.)ebrary, Inc, ja Peter G. Melark. Comets: Characteristics, Composition and Orbits. Hauppauge, N.Y.: Nova Science Publishers, 2012.
MLA-viite (9. p.)ebrary, Inc, ja Peter G. Melark. Comets: Characteristics, Composition and Orbits. Nova Science Publishers, 2012.
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