A.K.Sharma, V. K. Gahlot, P. Kalla, and P. P. Dahale. “MaaS: Opportunities for Improving Mobility Services”. Helix - The Scientific Explorer | Peer Reviewed Bimonthly International Journal, vol. 10, no. 01, Feb. 2020, pp. 149-57, https://helixscientific.pub/index.php/home/article/view/75.