PEP Intermedius is a network of cash merchants that serves as the bridge for unbanked customers and the financial system.
Bridges to cash: The Retail End of M-PESA,

A leading academic paper on Understanding liquidity needs in different environments, co-authored by PEP-chairman Frederik Eijkman and entitled Bridges to cash: The Retail End of M-PESA, was published on the website of the Social Science Research Network (SSRN).

http://papers.ssrn.com/sol3/papers.cfm?abstract_id=1655248