The book series I am writing, HellFire Catharsis, contains several Touhou references:
There are characters named Remilia, Patchouli, Murasa, Yuyuko, and Cirno.
The third book is called "Bloom Nobly, Sakura Girl". As you would expect, it takes place in Japan.
The way mages fight is basically ripped from IaMP.
All important characters have theme songs (which are going to be composed by me). A few are similar to Touhou names: Grigio's "France?s Millennium~Medicine?s History", Yuyuko's "Border of Life", Jennifer's "Border of Death", Remilia's "Septette For The Scarlet Queen", Christia's "Maybe She Was U.N.Owen?", and Marina's "Be Wary Of The Novus Left Behind".
Hell, this "every character has a theme song" thing was from how much I loved Touhou; it made me want to become a Composer.