Klein, Nicholas (2009). "Emergent Curbside Intercity Bus Industry". Transportation Research Record: Journal of the Transportation Research Board. 2111: 83–89. doi:10.3141/2111-11. S2CID109266853.
Klein, Nicholas (2009). "Emergent Curbside Intercity Bus Industry". Transportation Research Record: Journal of the Transportation Research Board. 2111: 83–89. doi:10.3141/2111-11. S2CID109266853.