Source Data Reference for:

City = Geneva
Time = 1850

City	Year	Size	Size Comment	Year Comment	Author	Title	Location
Geneva	1850	45,000			Paul Bairoch	La population des villes europeennes de 800 a 1850
Geneva	1850	31,200			Jan Lahmeyer	http://www.populstat.info/	n/a
Geneva	1850	42,000			Tertius Chandler	Four thousand years of urban growth	p26