classifications of inventory

for manufacturing company there are three different classifications of inventory.these are:
1- Raw materials- the individual parts and pieces that will be assembled to make the finished goods.
2- Work-in-progress- units of inventory for which production has started, but has not yet been completed.
3- finished goods- units that have been completed , but not yet sold.

Internal links :
1- this link about inventory and financial statement
http://thefutureofmoney.blogspot.com/2009/06/inventory-and-financial-statement.html
2- this link about valuing the inventory when it purchased
http://thefutureofmoney.blogspot.com/2009/06/valuing-inventory-when-it-purchased.html