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: 1996 D US Atlanta Olympic Rowing Commemorative BU Silver Dollar PCGS MS69
Product feature: 1996-D US Atlanta Olympic - Rowing Commemorative BU Silver Dollar, Certified PCGS MS69, Actual Silver Weight: 0.77344 oz. ASW
Product price: $227.50
Target attributes: Nationality
Answer: attribute: nationality
value: us
source: product title
attribute: nationality
value: us
source: product feature