Cubs attendance watch: Thoughts about the Cardinals series and pricing - Bleed Cubbie Blue
The History of the Chicago Cubs – Giordanos
A Day In Wrigley Field History: April 10, 1997 - Bleed Cubbie Blue
One Place That Hasn't Seen The Light - Sports Illustrated Vault
Wrigley Field: A Century of Survival – Society for American Baseball Research
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A Day In Wrigley Field History: April 6, 1971 - Bleed Cubbie Blue
A Day In Wrigley Field History: April 17, 1923 - Bleed Cubbie Blue
Attend-O-Meter - Chicago Cubs 2004 Attendance Analysis
List of events at Wrigley Field - Wikipedia
Wrigley Field historical sleuthing: A very small crowd - Bleed Cubbie Blue
Baseball history unpacked, May 15 - Bleed Cubbie Blue
Wrigley Field historical sleuthing: 1929 edition - Bleed Cubbie Blue
Wrigley Field historical sleuthing: Old scoreboard edition - Bleed Cubbie Blue
Cubs historical sleuthing: A moment in time from 1989 - Bleed Cubbie Blue