PayPal Please, select an option. Regular rate (from 15th June 2025 to 14th September 2025) SIS member (2025 SIS membership not paid) 350,00 € EUR SIS member (fees paid up to 2025) 290,00 € EUR Junior SIS member (under 35, 2025 SIS membership not paid) 255,00 € EUR Junior SIS member (under 35, fees paid up to 2025) or retired m 220,00 € EUR Non SIS member 390,00 € EUR Non SIS member (Ph.D. student) 355,00 € EUR