@book{Stengel, author = {Stengel, E.}, title = {Suicide and attemted suicide, Harmondsworth (Penguin Books) 1971.}, language = {en} } @book{Stengel, author = {Stengel, E.}, title = {Suicide and Attempted suicide. Harmondsworth (Penguin) 1964.}, language = {en} }