大幹道
1 2 K. M. Sarkar (1927). The Grand Trunk Road in the Punjab: 1849-1886. Atlantic Publishers & Distri. pp. 2–. GGKEY:GQWKH1K79D6. https://books.google.co.jp/books?id=qFdJbRywbKwC&pg=PA2&redir_esc=y&hl=ja
↑ Chaudhry, Amrita (2012年5月27日). “Cracks on a historical highway”. The Indian Express. オリジナルの2013年5月22日時点におけるアーカイブ。. https://web.archive.org/web/20130522025746/http://www.indianexpress.com/news/cracks-on-a-historical-highway/954273/0 quote: What Chandragupta had begun, his grandson Ashoka perfected. Trees were planted, ... Serais built. p.2
↑ David Arnold; Science, technology, and medicine in colonial India (New Cambr hist India v.III.5) Cambridge University Press, 2000, 234 pages p.