Iūpiter is thought to be the historically older form and Iuppiter, to have arosen through the so-called littera-rule. Compare Weiss (2010). „Observations on the littera rule”(PDF). Cornell Phonetics Lab. Ithaca, NY: Cornell University. Архивирано из оригинала(PDF) 2016-10-17. г.
Iūpiter is thought to be the historically older form and Iuppiter, to have arosen through the so-called littera-rule. Compare Weiss (2010). „Observations on the littera rule”(PDF). Cornell Phonetics Lab. Ithaca, NY: Cornell University. Архивирано из оригинала(PDF) 2016-10-17. г.