Title: Variability of emission lines in quasar spectra
Abstract: Analysis of ultraviolet spectra of quasars obtained with IUE indicate that the permitted emission lines in quasar spectra are variable. The upper limit for the delay between a change in the continuum and the consequential change in the emission lines is about 9 months. This rapid response of the permitted emission lines to changes in the continuum leads to a number of problems in understanding the nature of quasars.