(define merge (lambda (sorted-ntpl1 sorted-ntpl2) (cond ((null? sorted-ntpl1) sorted-ntpl2) ((null? sorted-ntpl2) sorted-ntpl1) ((< (car sorted-ntpl1) (car sorted-ntpl2)) (cons (car sorted-ntpl1) (merge (cdr sorted-ntpl1) sorted-ntpl2))) (else (cons (car sorted-ntpl2) (merge sorted-ntpl1 (cdr sorted-ntpl2)))) )))