Instruction: First, identify the target attributes from the provided list. Then, scan the product title, description, feature, and brand to extract the values associated with each target attribute. Finally, create a list of dictionaries, each containing the extracted attribute, its corresponding value, and the source where it was found.

Input:
Product title: Birkenstock Womens Delhi Lux Sandal
Product description: Birkenstock DELHI LUX BLACK LTR 39
Product feature: Leather, Birkenstock DELHI LUX BLACK LTR 39, Package Dimensions: 12.3 x 5.8 x 4.4 inches, Shipping Weight: 1.2 pounds, ASIN: B01DV3IWQQ, Item model number: 744203, Date first listed on Amazon: April 5, 2016, Average Customer Review: 3.8 out of 5 stars 4 customer reviews
Product brand: Birkenstock
Target attributes: Silhouette
Answer: attribute: silhouette
value: None
source: None