digraph G {
net [label="gsm_network"]
subconns [label="subscr_conns"]
sub [label="gsm_subscriber"]
subcon [label="gsm_subscriber_conn"]
subgrp [label="gsm_subscriber_group"]
net -> subconns
subconns -> subcon [label="llist"]
subcon -> sub
subcon -> net
sub -> subgrp
subgrp -> net
}