@ARTICLE{nonnengartIGPL98,
        AUTHOR             = {Andreas Nonnengart},
        TITLE              = {Modal Frame Characterization by Way of Auxiliary Modalities},
        JOURNAL            = {Journal of the IGPL},
        YEAR               = {1998},
        VOLUME             = {6},
        NUMBER             = {6},
        PAGES              = {875 -- 899}
}