www.adassoc.org.uk
The Advertising Association is a federation of trade bodies representing the advertising and promotional marketing industries including advertisers, agencies media and support agencies.

www.courseworkbank.co.uk/coursework/factors_affecting_demand_mobile_telephony_products_2572/
From coursebank.co.uk, a database of essays and coursework – factors affecting demand for mobile telephony products.

http://knowledge.wharton.upenn.edu/index.cfm?fa=viewArticle&id=792
Links to Raju & Zhang’s article “Choosing the Wrong Pricing Strategy Can Be a Costly Mistake” in Knowledge@Wharton. You may have to register first but this is free.