Key Words:
Bratislava Coronation 400th Anniversary; International Chemistry Olympiad: 50th Anniversary; Personalized Stamps [Slovak]: Floral Motif; Technical Monuments Issues [Slovak]: Piešťany Power Plant; EUROPA Issues [Slovak]: 2018; Natural Heritage Issues [Slovak]: Poprad-Matejovce Archaelogical Area; Joint Issues [Slovak]: Vatican City: Slovak Liturgical Language