1 Chronicles 2:3

The sons of Judah: Er, Onan and Shelah. These three were born to him by a Canaanite woman, the daughter of Shua. Er, Judah's firstborn was wicked in Jehovah's sight; so Jehovah put him to death.

Genesis 38:2-10

Judah met a young Canaanite woman there whose father was named Shua. He married her.

Genesis 46:12

The sons of Judah were Er, Onan, Shelah, Perez, and Zerah. (Er and Onan died in Canaan.) The sons of Perez were Hezron and Hamul.

Numbers 26:19

Er and Onan were sons of Judah, but they died in Canaan.

1 Chronicles 9:5

Of the Shilonites: Asaiah the firstborn and his sons.

Treasury of Scripture Knowledge

Summary

The sons of Judah; Er, and Onan, and Shelah: which three were born unto him of the daughter of Shua the Canaanitess. And Er, the firstborn of Judah, was evil in the sight of the LORD; and he slew him.

Bible References

Er, and

1 Chronicles 9:5
Of the Shilonites: Asaiah the firstborn and his sons.
Genesis 38:2
Judah met a young Canaanite woman there whose father was named Shua. He married her.
Genesis 46:12
The sons of Judah were Er, Onan, Shelah, Perez, and Zerah. (Er and Onan died in Canaan.) The sons of Perez were Hezron and Hamul.
Numbers 26:19
Er and Onan were sons of Judah, but they died in Canaan.