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: Gavitt's Stock Exchange Board Game
Product description: All aboard for the exciting and popular stock trading game: Gavitt’s Stock Exchange. Deal and trade your cards to capture a share of the railway stock market. Be first to get all the cards of one railway line, call out Topeka and you’ll win that hand. This version is a faithful reproduction of the original top-selling game first printed in 1903. For 3 to 6 players.
Product feature: Gavitt's Stock Exchange is a faithful reproduction of the wildly popular card game from 1903, Comes with reproductions of packaging, cards, rules, marketing literature; modern rules and game history, Packaged in collectible tin, For 3-6 players, ages 7 to adult, From the maker of Apples to Apples
Product brand: Heirloom Games
Target attributes: Maximum Players
Answer: attribute: maximum players
value: to 6 players
source: product description
attribute: maximum players
value: -6 players
source: product feature