Rock-a-bye Baby
From Tardis Wiki, the free Doctor Who reference
Rock-a-bye Baby was an Earth lullaby.
Nancy sang it to Jenkins, who had become infected with the Empty Child plague. She continued to sing at the Ninth Doctor's request to keep Jenkins sleeping as the Doctor freed her from her handcuffs. (TV: The Empty Child)
Jasper Adeola sang it to Tanya Adeola, his daughter. (PROSE: The Stone House)
The song went: