TY  - JOUR
TI  - Simple formulas for standard errors that cluster by both firm and time
AU  - Samuel Brodsky Thompson
JO  - Journal of Financial Economics
PY  - 2010
VL  - 99
IS  - 1
DO  - 10.1016/j.jfineco.2010.08.016
UR  - https://doi.org/10.1016/j.jfineco.2010.08.016
ER  -