(原始内容存档于2023-11-09) (英语). Rafaat, Aram. Kurdistan in Iraq: The Evolution of a Quasi-State. Routledge. 2018-05-11 [2023-12-25]. ISBN 978-1-351-18881-4. (原始内容存档于2023-11-09)
that the set of finite trees over a well-quasi-ordered(英语:well-quasi-ordering) set of labels is itself well-quasi-ordered under homeomorphic(英语:homeomorphism
5868––5871. doi:10.1103/PhysRevLett.84.5868. Bose–Einstein condensation of quasi-equilibrium magnons at room temperature under pumping. Nature. 28 September