A Model of Oil Supply 17 supplying capacity cosuming capacity 17 16 18 a 20 20 12 12 17 10 15 30 >(e h 60 20 20 20 Vertices: b 13 30 a,b:refineries g,h,i:markets others:relays 17 pipeline,with max capacity/weekA Model of Oil Supply a b c d f e g h i S 20 60 D 20 30 20 16 18 12 17 10 7 13 30 20 15 Vertices: a, b: refineries g, h, i: markets others: relays 17 pipeline, with max capacity/week 17 17 supplying capacity cosuming capacity 12 20