| | *Alice Duggan Gracy, "Willis Twichell, Civil Engineer." Gracy was the daughter of a short-term Texas state senator, Arthur Pope Duggan, Sr. (1876-1935), an [[attorney]] and [[real estate]] developer from Stamford, Texas, who was married to a niece of George Washington Littlefield.<ref>{{cite web|url=https://legacy.lib.utexas.edu/taro/ttusw/00018/tsw-00018.html|title=Alice Duggan Gracy: An Inventory of Her Papers, 1910-1951|publisher=Southwest Collection/Special Collections Library in [[Lubbock]]|accessdate=October 14, 2019}}</ref> | | *Alice Duggan Gracy, "Willis Twichell, Civil Engineer." Gracy was the daughter of a short-term Texas state senator, Arthur Pope Duggan, Sr. (1876-1935), an [[attorney]] and [[real estate]] developer from Stamford, Texas, who was married to a niece of George Washington Littlefield.<ref>{{cite web|url=https://legacy.lib.utexas.edu/taro/ttusw/00018/tsw-00018.html|title=Alice Duggan Gracy: An Inventory of Her Papers, 1910-1951|publisher=Southwest Collection/Special Collections Library in [[Lubbock]]|accessdate=October 14, 2019}}</ref> |
| | * Fred M. Truett, ''Texas Was His Land'' (Austin: Eakin Press, 1982). | | * Fred M. Truett, ''Texas Was His Land'' (Austin: Eakin Press, 1982). |
| | * Sue Watkins, ed., ''One League to Each Wind: Accounts of Early Surveying in Texas'' (Austin: Surveyors Association Historical Committee, c. 1964). name=handbook/> | | * Sue Watkins, ed., ''One League to Each Wind: Accounts of Early Surveying in Texas'' (Austin: Surveyors Association Historical Committee, c. 1964). name=handbook/> |