Instruction: Using the product's title, description, features, price, and brand, identify and retrieve the values associated with a specified set of target attributes. Output the extracted values along with their respective sources (e.g., title or feature) indicating where each value was found.

Input:
Product title: 2001 Proof American Eagle Silver Dollar with Original Packaging & Certificate of Authenticity.
Product description: 2001-W Proof Silver American Eagle
Product feature: 1 oz. Pure Silver, .999 Fine Silver, U.S. Mint Issued, Packed as U.S. Mint issued
Target attributes: US Special Variety
Answer: attribute: us special variety
value: american eagle
source: product description
attribute: us special variety
value: american eagle
source: product title