The pipeline's design is based on a trilateral agreement signed in March 2007 in Athens by Putin, then Greek Prime Minister Costas Karamanlis and former Bulgarian Prime Minister Sergei Stanishev.
Nacrt naftovoda temeljen je na trilateralnom sporazumu koji su u ožujku 2007. godine u Ateni potpisali Putin, tadašnji grčki premijer Costas Karamanlis i bivši bugarski premijer Sergei Stanishev.