RT Journal T1 A Note on Covariance Matrix Estimation in Quantile Regressions A1 Hongtao Guo,Zhijie Xiao PB Front. Econ. China FD 2014-07-04 YR 2014 JF Frontiers of Economics in China JO Front. Econ. China VO 9 IS 2 SP 165 DO 10.3868/s060-003-014-0009-3 K1 bandwidth selection;expansion;quantile regression LK {https://academic.hep.com.cn/fec/EN/article/article_10866.shtml}