Analysis of information sources in references of the Wikipedia article "Modal jazz" in English language version.
Well Tizol did the melody, and he said that, you know, he used to hear those unusual melodies, because in Puerto Rico where he studied, they were very poor and they couldn't afford too much music. So in order to make them get more practice and get varied compositions, they'd turn the music upside down. And the result, you get that modal sound that comes from most of the things Tizol's involved in.
