Research on Tchaikovsky
In 2014 I completed a dissertation dealing with textural aspects to Tchaikovsky's style. It focuses on the fact that his style relies heavily on thematically based counterpoint, a finding running counter to the majority of previous musicography.
You can read it online here.
The importance of thematic counterpoint is not just valid for his symhonies, but for his orchestral, chamber and operatic production in general.