1> (define doc-ast
(html
(head (title "Demo Links"))
(body
...)))
2 > (extract-links doc-ast)
("http://www.acm.org/dl" "http://www.ieee.org/ieeexplore/" "http://www.w3c.org"
"http://link.springer.de/link/service/series/0558/" "http://www.cs.auc.dk"
"http://www.auc.dk")