Grateful acknowledgement is made to the following sources:
Photographs and images
Pyramids of peanut (groundnut) bags, Maiduguri, Nigeria : Encyclopaedia Britannica Concise
Resource 4 : 3D objects : Original Source:(Accessed 2008)
Resource 5 : Recording results : Original Source: http://www.bbc.co.uk (Accessed 2008)
Every effort has been made to contact copyright holders. If any have been inadvertently overlooked the publishers will be pleased to make the necessary arrangements at the first opportunity.