Instruction: Parse the product information to locate the target attribute, and then provide the extracted value of the target attribute and its source in the output, specifying None if the attribute is not present.

Input:
Product title: Polo Ralph Lauren Men's Torrington Wingtip Oxford
Product description: Classic and authentic, Polo is the foundation of the world of Ralph Lauren menswear, combining the time-honored aesthetic of East Coast Ivy League casual style with proper English refinement. Often imitated but never matched, Polo is a true symbol of the preppy lifestyle. The iconic polo player logo is recognized worldwide as a symbol of heritage and authenticity.
Product feature: 100% Leather, Imported, Rubber sole, Heel measures approximately 1", Classic pinking-edged wingtip oxford in two casual tones, Embossed logo at heel, Allover broguing details, Package Dimensions: 14.5 x 8.9 x 4.8 inches, Shipping Weight: 2.7 pounds, ASIN: B00HDPNVKG, Item model number: Torrington Wingtip, Date first listed on Amazon: May 1, 2014, Domestic Shipping: Item can be shipped within U.S., International Shipping: This item is not eligible for international shipping. Learn More, Average Customer Review: 4.1 out of 5 stars 33 customer reviews
Product brand: Polo Ralph Lauren
Target attributes: Silhouette
Answer: attribute: silhouette
value: wingtip
source: product title
attribute: silhouette
value: oxford
source: product feature
attribute: silhouette
value: wingtip
source: product feature