Source Data Reference for:

City = Barletta
Time = 1800

City	Year	Size	Size Comment	Year Comment	Author	Title	Location
Barletta	1800	16,000			Paul Bairoch	La population des villes europeennes de 800 a 1850
Barletta	1820	17,100			Valentin Parisot	Dictionnaire geographique universelle