Encyclopedia of Major Marketing Campaigns (offsite, Library Services Center - REFERENCE HF5837.E53 2000) - Dated but still of use.
For Coca-Cola -- Fifty Years of Coca-Cola Television Advertisements - 1951-1999, archived online from the Library of Congress
Tip: Do an Advanced Search in periodical databases with the product name ; combine with a concept:
1st search box: coke zero
2nd search box: advertising or marketing or promotion*