The Schubertians is, or was, a small group of male singers at the University of California at Santa Barbara under the direction of Carl Zytowski between the years of 1964 to 1995, when Mr. Zytowski finally officially retired. Mr. Zytowski, or Mr. Z, as he is affectionately known by his pupils, can be reached at firstname.lastname@example.org. If you are an old boy, I'm sure he would appreciate hearing from you.
You can get some of Mr. Z's publications on line here at ChoralWeb. Some spirituals, several Christmas carols, and the Wreath of Epitaphs are available.
This button will take you directly to Mr. Z's published works on Choralweb: