RosettaCodeData/Task/Remove-duplicate-elements/Scheme/remove-duplicate-elements-1.scm

(define (remove-duplicates l)
  (cond ((null? l)
         '())
        ((member (car l) (cdr l))
         (remove-duplicates (cdr l)))
        (else
         (cons (car l) (remove-duplicates (cdr l))))))

(remove-duplicates '(1 2 1 3 2 4 5))