Source Data Reference for:

City = Cologne
Time = 1400

City	Year	Size	Size Comment	Year Comment	Author	Title	Location
Cologne	1400	40,000			Paul Bairoch	La population des villes europeennes de 800 a 1850
Cologne	1400	40,000			Tertius Chandler	Four thousand years of urban growth	p539
Cologne	1400	40,000			Tertius Chandler	Four thousand years of urban growth	"p8, p18"
Cologne	1400	40,000			Tertius Chandler	Four thousand years of urban growth	p513