Graham Stack  has written and produced hit records for many artists including a singer who relinquished her American what?
Tina Turner Tina Turner (born Anna Mae Bullock; November 26, 1939), is an American-born Swiss recording singer, songwriter, dancer, actress, and author. Born and raised in the Southeastern United States, Turner relinquished her American citizenship after obtaining Swiss citizenship in 2013.
Gwen Guthrie Gwendolyn "Gwen" Guthrie (July 9, 1950 – February 3, 1999) was an American singer-songwriter and pianist, who also sang backing vocals for Aretha Franklin, Billy Joel, Stevie Wonder, Peter Tosh, and Madonna, among others, and who wrote songs made famous by Ben E. King, Angela Bofill and Roberta Flack.