need clarification edit

If Le Van Huu's work was lost during the 4th Chinese domination of Vietnam which ended in 1427, and if Ngo Si Lien did not write his work until 1479, then how could Ngo Si Lien have used Le Van Huu's work? I'm sure there is a good answer to this question, but the first paragraph of the article makes a puzzle out of it, so maybe someone who has knowledge on the matter can clear it up.