APA (7th ed.) Citation

Wagner, S. (1993). Variability in active galaxies. The need for a dedicated optical quasar monitoring telescope.

Chicago Style (17th ed.) Citation

Wagner, Stefan. "Variability in Active Galaxies." The Need for a Dedicated Optical Quasar Monitoring Telescope 1993.

MLA (9th ed.) Citation

Wagner, Stefan. "Variability in Active Galaxies." The Need for a Dedicated Optical Quasar Monitoring Telescope, 1993.

Warning: These citations may not always be 100% accurate.