Jon Lester's retirement reminds us Red Sox never should have let him go
Jon Lester retires: Former Red Sox, Cubs ace concludes 16-year career - Sports Illustrated
Jon Lester, Former Red Sox Ace and World Series Champ, Retires From MLB – NBC Chicago
Jon Lester has announced his retirement - Bleed Cubbie Blue
A look back at Jon Lester's career - Beyond the Box Score
Former Cubs pitcher Jon Lester, part of team's World Series core, announces his retirement - Chicago Sun-Times
Jon Lester traded to Oakland Athletics, Yoenis Cespedes to Boston Red Sox - ESPN
Jon Lester retires after epic MLB career as Red Sox, Cubs ace - Sports Illustrated
Former Red Sox ace Jon Lester, three-time World Series champ, retires after 16 seasons - The Boston Globe
Jon Lester hits free agency after Cubs decline option; is a Boston Red Sox reunion possible?