Balasubramanya, S., Evans, B., Hardy, R., Ahmed, R., Habib, A., Asad, N.S.M., Rahman, M., Hasan, M., Dey, D., Fletcher, L., Camargo-Valero, M.A., Chaitanya Rao, K., and Fernando, S., “Towards sustainable sanitation management : establishing the costs and willingness to pay for emptying and transporting sludge in rural districts with high rates of access to latrines”, vol. 12, no. 3, p. e0171735 - , 2017.