@book{han-nom-d8-nefd-ye22,
  title = {Cửu chương lập thành toán pháp 九章立成併法},
  url = {https://www.viet-dien.com/t/han-nom-d8-nefd-ye22/5},
  pages = {5},
  note = {held by Columbia University Libraries},
  urldate = {2026-09-10},
}