Phanikumar CV, Maitra B. Valuing urban bus attributes: an experience in Kolkata. J Public Transport. 2006;9(2):69-87. doi: 10.5038/2375-0901.9.2.4
Phani Kumar CV, Basu D, Maitra B. Modeling generalized cost of travel for rural bus users: a case study. J Public Transport. 2004;7(2):59-72. doi: 10.5038/2375-0901.7.2.4
Rothman KJ, Glass RL, Espinal F, Velez H. Caries-free teeth in the absence of fluoride ion. J Public Health Dent. 1972;32(4):225-8. doi: 10.1111/j.1752-7325.1972.tb03977.x