Johannes Kepler, Harmonices Mundi [The Harmony of the World] (Linz, (Austria): Johann Planck, 1619), hlm. 189. Pada bagian bawah hlm. 189: "Sed res est certissima extactissimaque quod proportio qua est inter binorum quorumcunque Planetarum tempora periodica, sit præcise sesquialtera proportionis mediarum distantiarum, id est Orbium ipsorum; ..."
Dalam bahasa Inggris: "But it is absolutely certain and exact that the proportion between the periodic times of any two planets is precisely the sesquialternate proportion [i.e., the ratio of 3:2] of their mean distances, that is, of the actual spheres, ..."
Terjemahan dalam bahasa Inggris dari Harmonices Mundi karya Kepler tersedia sebagai: Johannes Kepler with E. J. Aiton, A. M. Duncan, and J. V. Field, trans., The Harmony of the World (Philadelphia, Pennsylvania: American Philosophical Society, 1997); lihat khususnya hlm. 411.
books.google.com
Johannes Kepler, Harmonices Mundi [The Harmony of the World] (Linz, (Austria): Johann Planck, 1619), hlm. 189. Pada bagian bawah hlm. 189: "Sed res est certissima extactissimaque quod proportio qua est inter binorum quorumcunque Planetarum tempora periodica, sit præcise sesquialtera proportionis mediarum distantiarum, id est Orbium ipsorum; ..."
Dalam bahasa Inggris: "But it is absolutely certain and exact that the proportion between the periodic times of any two planets is precisely the sesquialternate proportion [i.e., the ratio of 3:2] of their mean distances, that is, of the actual spheres, ..."
Terjemahan dalam bahasa Inggris dari Harmonices Mundi karya Kepler tersedia sebagai: Johannes Kepler with E. J. Aiton, A. M. Duncan, and J. V. Field, trans., The Harmony of the World (Philadelphia, Pennsylvania: American Philosophical Society, 1997); lihat khususnya hlm. 411.
