english: Blumenstock’s research began when he partnered with the largest mobile phone provider in Rwanda, and the company provided anonymized transaction records from about 1.5 million customers between 2005 and 2009.
non_english: Riset Blumenstock wiwit nalika dheweke partner karo penyedia ponsel paling gedhé ing Rwanda, lan perusahaan nyedhiyakake rekaman transaksi anonim saka sekitar 1.5 yuta pelanggan antarane 2005 lan 2009.