linear recursion added by int0X80 on Sat Jan 26 17:53:40 2013
define (sum term a next b) (define (iter a result) (if <??> <??> (iter <??> <??>))) (iter <??> <??>))
define (sum term a next b) (define (iter a result) (if <??> <??> (iter <??> <??>))) (iter <??> <??>))