Mishneh Torah — Transmission of the Oral Law מסירת תורה שבעל פה, Chapter 20

וּמִכְּלַל הַחֲכָמִים שֶׁקִּבְּלוּ מֵרָב הוּנָא וּמֵרָב יְהוּדָה, רַבָּה וְרָב יוֹסֵף. וּמִכְּלַל הַחֲכָמִים שֶׁקִּבְּלוּ מֵרַבָּה וְרָב יוֹסֵף, אַבַּיֵי וְרַבָּא; וּשְׁנֵיהֶם קִבְּלוּ גַּם מֵרָב נַחְמָן. וּמִכְּלַל הַחֲכָמִים שֶׁקִּבְּלוּ מֵרַבָּא, רָב אַשֵׁי וְרַבִּינָא; וּמָר בַּר רָב אַשֵׁי קִבַּל מֵאָבִיו וּמֵרַבִּינָא.

Among the Sages who received the tradition from Rav Huna and Rav Yehudah were Rabbah and Rav Yosef. Among the sages who received the tradition from Rabbah and Rav Yosef were Abbaye and Ravva. Both of them also received the tradition from Rav Nachman. Among the Sages who received the tradition from Ravva were Rav Ashi and Ravina. Mar bar Rav Ashi received the tradition from Rav Ashi, his father, and from Ravina.