The Council of State, Greece's highest administrative court, is hearing a case brought by two private citizens who are seeking to have Sunday's referendum ruled unconstitutional and cancelled. A separate group has filed a counter-motion supporting the referendum's legality. Spyridon Nicolaou is one of the two who are trying to have Sunday's popular vote called off. He tells The Associated Press: "The referendum is invalid because it expressly violates the constitution, which stipulates that a referendum cannot take place on economic matters. But it's also invalid because it doesn't incorporate the text of the documents on which the Greek people are called on to decide. Would anyone from Evros (in Greece's far northeast) know the specific documents?" Dimitris Belantis is one of those seeking to ensure the vote goes ahead. He says the referendum doesn't violate the constitution, noting that votes can be held on "crucial national matters" which could include economic ones.