@article {IOPORT.03515456,
    author       = {Monien, Burkhard},
    title        = {Transformational methods and their application to complexity problems.},
    year         = {1976},
    journal      = {Acta Informatica},
    volume       = {6},
    issn         = {0001-5903},
    pages        = {95-108},
    publisher    = {Springer, Berlin},
    doi          = {10.1007/BF00263746},
    identifier   = {03515456},
}