@book{han-nom-d8-nefd-ye22,
  title = {Cửu chương lập thành toán pháp 九章立成併法},
  url = {https://viet-dien.com/t/han-nom-d8-nefd-ye22/6},
  pages = {6},
  note = {held by Columbia University Libraries},
  urldate = {2026-09-15},
}