Companies belonging to billionaires Radovan Vítek, Karel Komárek Jr. and Petr Kellner — the richest Czech — together control almost 60 percent of Sazka’s bonds. International lawyers are reported to have sent a letter notifying troubled lottery firm Sazka that they are using an option in the bonds’ fine print that allows them to demand quicker debt repayment. Sazka claims it has already met its payments and will go to court.