Sisters send Mother's Day card back-and-forth for 20 years in memory of mom

NEWARK, Delaware -- Brenda and Donna, two sisters from Delaware, have sent the same Mother's Day card to each other for 20 years.

Each time it arrives in their mailbox, they add messages and photos that evoke memories of mom.

Both have become mothers themselves.

And between them, three of their children serve in the military.