Robust estimation in partial linear mixed model for longitudinal data (Q1003901)

The authors employed robust generalized estimating equations to analyze partial linear mixed models for longitudinal data. This work is significant. I would like to recommend the paper for publication subject to some minor revisions, which would take the following comments into consideration: 1. Describe the relationships between this paper and the former authors' paper, Robust estimation in generalized semiparametric mixed models for longitudinal data. J. Multivariate Anal. 98, No. 8, 1658--1683 (2007; Zbl 1122.62029). 2. Is it necessary to assume that \(e_{ij}\sim N (0, \sigma^2_o)?\) 3. Correct grammatical errors.