<div><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">What do you mean by pointers? Boxes? </blockquote></div> I'd never heard about box during my classes... By pointers, I mean that some objects are referenced by something that looks like C pointers Here is an example : (define list '(a b c)) (define copy list) (set-car! copy 'z) ; Now list is '(z b c) If I want to duplicate the information stored in list, I have to write (define copy `(,@list)) >(define (copy v) > (deserialize (serialize v)) That produce the result that I want Thanks you your answer -- Cyprien Nicolas <a href="mailto:c.nicolas@gmail.com">c.nicolas@gmail.com</a>