On sphere orders
Tài liệu tham khảo
Brightwell, 1989, Sphere orders, Order, 6, 235, 10.1007/BF00563524
Fon-Der-Flaass, 1992, A note on sphere containment orders, Order, 10, 143, 10.1007/BF01111298
Hurlbert, 1988, A short proof that N3 is not a circle containment order, Order, 5, 235, 10.1007/BF00354890