Source Data Reference for:

City = Kaliningrad
Time = 1800

City	Year	Size	Size Comment	Year Comment	Author	Title	Location
Kaliningrad	1800	60,000			Paul Bairoch	La population des villes europeennes de 800 a 1850
Kaliningrad	1800	55,600			Jan Lahmeyer	http://www.populstat.info/	n/a
Konigsberg	1800	53,000			Tertius Chandler	Four thousand years of urban growth	p486
Konigsberg	1800	53,000			Tertius Chandler	Four thousand years of urban growth	p23
Konigsberg	1800	59,000			Jan De Vries	European urbanization 1500-1800	p273