"The Illusion of Diversity: Visualizing Ownership in the Soft Drink Industry" [msu.edu] consists of an elaborate cluster diagram of all the soft drink brands and varieties found in the refrigerator cases of about 100 Michigan retailers, along with their ownership or licensing connections.
It reveals the occurrence of "pseudovariety," or the illusion of diversity, concealing a lack of real choice, as only 3 firms control 89% of US soft drink sales (i.e. Coca Cola, Pepsi and Dr. Pepper Snapple Group). The survey included a complete inventory of soft drinks in the refrigerator cases of 94 different food retailers. It recorded 987 varieties of soft drinks, sold under 195 brands, and 102 parent companies. But over 300 varieties were found in only one store each.