|aaaa1|aaaa2|aaaa3|aaaa1|aaaa2|aaaa3|aaaa1|aaaa2|aaaa3|
+-----+-----+-----+-----+-----+-----+-----+-----+-----+
*/
|aaaa1|aaaa2|aaaa3|aaaa1|aaaa2|aaaa3|aaaa1|aaaa2|aaaa3|
+-----+-----+-----+-----+-----+-----+-----+-----+-----+
*/
size_t n_refs = 0;
add_references (pt, title, refs, &n_refs);
add_references (pt, layers, refs, &n_refs);
size_t n_refs = 0;
add_references (pt, title, refs, &n_refs);
add_references (pt, layers, refs, &n_refs);