https://twainsgeography.com/bibcite/reference/24
https://twainsgeography.com/bibcite/reference/18
https://twainsgeography.com/bibcite/reference/64
https://twainsgeography.com/bibcite/reference/60
https://twainsgeography.com/bibcite/reference/61
https://twainsgeography.com/bibcite/reference/63
https://twainsgeography.com/bibcite/reference/62
https://twainsgeography.com/bibcite/reference/59
https://twainsgeography.com/bibcite/reference/58