In the introductory post to this blog, I wrote that in studying cadence figures in the upper tetrachord of the scale, "I noticed the variety of treatments of scale degree ^6 as the ninth of a dominant ninth chord. This blog is intended to document some of those, especially in the essential 19th century European repertoires of the musical stage and music for dance." Link to the introduction.
A subsequent post looked more closely at the different melodic and harmonic treatments of the dominant ninth: link to "On seven types of the dominant ninth."
I also announced publication of an essay, Dominant Ninth Harmonies in the 19th Century: link to the post. Link to the essay on Texas ScholarWorks. This is intended as a gallery of simple (clear) examples from the repertoire.