Officially this song is credited to Elvis Presley and Vera Matson, but neither of them wrote the song. Vera Matson was Ken Darby's wife, who was credited instead of Darby because Presley was affiliated with BMI, Darby with ASCAP, and in those days it was not permitted for an ASCAP writer and a BMI writer to share credit on the same song. Elvis Presley was just "given" the credit, through a deal his manager, Colonel Parker, made with Ken Darby.
ELVIS PRESLEY MUSIC
ABG ELVIS SONGS
SONGS OF KOBALT MUSIC PUBLISHING