Linked list in graphviz

linked_list.dot

digraph foo {
        rankdir=LR;
        node [shape=record];
        a [label="{ <data> 12 | <ref>  }", width=1.2]
        b [label="{ <data> 99 | <ref>  }"];
        c [label="{ <data> 37 | <ref>  }"];
        d [shape=box];
        a:ref:c -> b:data [arrowhead=vee, arrowtail=dot, dir=both, tailclip=false, arrowsize=1.2];
        b:ref:c -> c:data [arrowhead=vee, arrowtail=dot, dir=both, tailclip=false];
        c:ref:c -> d      [arrowhead=vee, arrowtail=dot, dir=both, tailclip=false];
}