"Schlaf." . . "søvn." . . "søvn" . . . . . . . . "Sleep : an active process" . . . . . . "Sleep: an active process research and commentary"@en . . . "Sleep: an active process : research and commentary" . "Sleep - an active process research and commentary. Contributing authors - dana C. Brooks [And others]" . . . . "Sleep : an active process : research and commentary" . "Sleep: an active process; research and commentary" . . . . . . "Sleep." . . . . "Sommeil." . . "sommeil." . "Sueño." . .