1. Date and name

Leviticus 16:29
Leviticus 23:27,32
Leviticus 25:9
Numbers 29:7

2. Rest from melachot , as on Shabbat

Leviticus 16:29,31
(Leviticus 23:3)
Leviticus 23:28,30-32
Numbers 29:7

3. Fasting ('tormenting the soul')

Leviticus 16:29,31
Leviticus 23:27,29,32
Numbers 29:7

4. Additional sacrifice

Leviticus 23:27
Numbers 29:8-11

5. Seder Ha'Avodah - Special ceremony by High Priest; forgiveness

Exodus 30:10
Leviticus 16:3-28; 30; 32-34
Leviticus 23:28
Numbers 29:11

6. Shofar blown on the Yovel (Jubilee)

Leviticus 25:9

7. Talmud

Mishnah Yomah
Babylonian Talmud, Tractate Yomah
Maimonides, Mishneh Torah, Laws of Repentance , 1-10
Laws of Rest from Occupation on the 10th , 1-3
Shulhan Aruch, Orah Hayim (and Mishnah Berurah) §§ 604-624

8. Sefer Hahinuch : Commandments 213 - 217, 264.