1. Abbreviations used: HPLC = high performance liquid chromatography; CCK = cholecystokinin; Boc = butyl oxycarbonyl; ODS = octadecylsilyl; rpm = revolutions per minute
2. Horizontal flow-through coil planet centrifuge equipped with a set of multilayer coils around the column holder
3. Chromatography of peptides on a multi-coil counter-current chromatograph
4. Conway, W. D. 1988.Countercurrent Chromatography. Theory and Practice, Edited by: Mandava, N. B. and Ito, Y. 443–464. New York: Marcel Dekker.