Source Data Reference for:

City = Cologne
Time = 1900

City	Year	Size	Size Comment	Year Comment	Author	Title	Location
Cologne	1875	166,000			Tertius Chandler	Four thousand years of urban growth	p520
Cologne	1900	437,000			Tertius Chandler	Four thousand years of urban growth	p536
Cologne	1900	437,000			Tertius Chandler	Four thousand years of urban growth	p540
Cologne	1900	437,000			Tertius Chandler	Four thousand years of urban growth	p492
Cologne	1900	372,500			Jan Lahmeyer	http://www.populstat.info/	n/a
Cologne	1914	621,000			Tertius Chandler	Four thousand years of urban growth	p504