History of retired numbers dates back to Lou Gehrig Day
Jackie Robinson: Biography, Baseball Player, Activist
Jackie Robinson, Biography, Statistics, Number, Facts, & Legacy
UCLA honors Jackie Robinson by retiring 42 across all sports
Why are MLB players wearing No. 42 jerseys today?
The Greatest MLB Showdown Project: Happy Jackie Robinson Day
Jackie Robinson - Wikipedia
42' is an inspiring tribute to Jackie Robinson
Jackie Robinson - Facts, Quotes & Stats
Jackie Robinson - Age, Bio, Birthday, Family, Net Worth