@unpublished{cc-hmbsm-20
, author =        "Cabello, Sergio and Colin~de Verdi{\`e}re, {\'E}ric"
, title =         "Hardness of minimum barrier shrinkage and minimum
                   installation path"
, year =          "2020"
, journal =       "Theoretical Computer Science"
, volume =         835
, pages =         "120--133",
, note =          "arXiv:1910.04228"
}