Source Data Reference for:

City = Castelvetrano
Time = 1850

City	Year	Size	Size Comment	Year Comment	Author	Title	Location
Castelvetrano	1850	18,000			Paul Bairoch	La population des villes europeennes de 800 a 1850
Castelvetrano	1853	13,500			n/a	Gothaischer Hofkalender