1. Acker, A., Marcout, J., Ochsenbein, F., Stenholm, B., Tylenda, R., Schohn, C.: In: The Strasbourg-ESO Catalogue of Galactic Planetary Nebulae. Parts I, II, European Southern Observatory, Garching (Germany), 1992, (1992). ISBN 3-923524-41-2. 1047 p.
2. Ali, A., Pfleiderer, J.: Astron. Astrophys. 351, 1036 (1999)
3. Ali, A., El-Nawawy, M.S., Pfleiderer, J.: Astrophys. Space Sci. 271, 245 (2000)
4. Ali, A., Sabin, L., Snaid, S., Basurah, H.M.: Astron. Astrophys. 541, A98 (2012)
5. Ali, A., Ismail, H.A., Snaid, S., Sabin, L.: Astron. Astrophys. 558, A93 (2013)