Wenham, E.J..
Planetary Astronomy / - 1st ed / - Essex CM20 2JE : Longman House. - p.41 :
0-582-32173-5
Mathematics
B9:74 / K9
Planetary Astronomy / - 1st ed / - Essex CM20 2JE : Longman House. - p.41 :
0-582-32173-5
Mathematics
B9:74 / K9