https://greekinter.net/arbitrage-%ce%8c%cf%87%ce%b9-%ce%b1%cf%85%cf%84%cf%8c-%cf%80%ce%bf%cf%85-%cf%80%ce%b5%cf%81%ce%af%ce%bc%ce%b5%ce%bd%ce%b1-%ce%94%cf%85%cf%83%cf%84%cf%85%cf%87%cf%8e%cf%82/