@article{El-Badry1961,
author = {El-Badry, M.A. },
title= {Failure of enumerators to make entries of zero: Errors in recording childless cases in population censuses},
year = {1961},
doi = {10.1080/01621459.1961.10482134},
journal = {Journal of the American Statistical Association },
volume = {56},
number = {296},
pages = {909--924},
}