Sally Peberdy & Jonathan Crush 
Calibrating Informal Cross-Border Trade in Southern Africa [PDF ebook] 

The study demonstrates that informal cross-border is a complex phenomenon and not uniform across the region, or even through border posts of the same country. However, the overall volume of trade, duties paid and VAT foregone, as well as the types of goods and where they are produced, indicate that this sector of regional trade should be given much greater attention and support by governments of the region as well as regional organizations such as the Common Market for Eastern and Southern Africa (COMESA), SADC and the Southern African Customs Union (SACU).