Repaso veraniego / Summer review / Перечитывая летом
https://moneditis.com/2014/10/20/real-de-a-ocho/
https://moneditis.com/2014/10/22/real-de-a-ocho-ii/
http://www.bbc.co.uk/ahistoryoftheworld/objects/JO391t6cRtGxstjbE4EEmg
https://en.wikipedia.org/wiki/Spanish_dollar
http://www.fuenterrebollo.com/faqs-numismatica/real-ocho.html