There are two sources of secondary research including internal sources and external sources. For the sales data the secondary sources include internal audit of sales invoices, orders, inquiries about products not stocked, returns details and customer calling sheets. Similarly financial data, storage data and transport data is collected through internal sources. The main sources of external secondary sources include government statistics, trade associations, commercial services and national & international institutions. Government statistics include population censuses, social surveys, Import/export statistics, agricultural statistics and production statistics which are very helpful in collecting secondary data. Trade associations can give the data through trade directory and, perhaps, a yearbook. International agencies like World Bank, IFAD, UNDP, IMF, ITC, FAO and ILO produce a plethora of secondary data which can be the other major sources of secondary data.