National Household Travel Survey, 2001: [United States]
2019 ◽
Vol 13
◽
pp. 143-149
◽
2015 ◽
Vol 12
(8)
◽
pp. 1139-1147
◽
2020 ◽
Vol 16
◽
pp. 100820
◽
2016 ◽
Vol 142
(6)
◽
pp. 04016021
◽