How to Tidy up a General Set-System by Use of Uncrossing Operations.

Alexander V. Karzanov How to Tidy up a General Set-System by Use of Uncrossing Operations. 215-225 1996 157 Theor. Comput. Sci. 2 db/journals/tcs/tcs157.html#Karzanov96 http://dx.doi.org/10.1016/0304-3975(95)00160-3