The key idea is this:
“To convert the texts to numerical sequences, sentence length was measured by the number of words (an alternative method of counting characters in the sentence turned out to have no major impact on the conclusions). The dependences were then searched for in the data — beginning with the simplest, i.e. linear. This is the posited question: if a sentence of a given length is x times longer than the sentences of different lengths, is the same aspect ratio preserved when looking at sentences respectively longer or shorter?”
I think this is implying that literature can have fractal qualities the way music can.
Interestingly the fractaliest work analyzed was A Heartbreaking Work of Staggering Genius by Dave Eggers.
Thanks Rudy Rucker for pointing me at this.