'BEGIN' 'COMMENT' LIBRARY 1; 'INTEGER' X, N, K; 'REAL' 'PROCEDURE' SIGMA(I, K, L, T); 'VALUE' L; 'INTEGER' I, K, L; 'REAL' T; 'BEGIN' 'REAL' X; X := 0; 'FOR' I := K 'STEP' 1 'UNTIL' L 'DO' X := T + X; SIGMA := X 'END' SIGMA; X := SIGMA(N, 1, 4, SIGMA(K, 1, N, 2) - 1); 'COMMENT' WORKING IN AUGUST 1960 AT AMSTERDAM; OUTREAL(99, X) 'END'