@article{White1980,
author = {White, H.},
title= {A Heteroskedasticity-Consistent Covariance Matrix Estimator and a Direct Test for Heteroskedasticity},
year = {1980},
doi = {10.2307/1912934},
journal = {Econometrica},
volume = {48},
number = {4},
pages = {817--830},
}