Peña, M.; Stasińska, G. (July 2001). Aguilar, A.; Carramiñana, A. (eds.). Planetary Nebulae with [WR] nuclei. IX Latin American Regional IAU Meeting, "Focal Points in Latin American Astronomy", held in Tonantzintla, Mexico, Nov 9-13, 1998. Revista Mexicana de Astronomía y Astrofísica, Serie de Conferencias. p. 61. Bibcode:2001RMxAC..11...61P.
Werner, K.; et al. (June 1992). "A spectacular mass-loss event of the central star of Longmore 4". Astronomy and Astrophysics. 259: L69–L72. Bibcode:1992A&A...259L..69W.
Corradi, R. L. M. (2003). Kwok, Sun; Dopita, Michael; Sutherland, Ralph (eds.). Observations of Planetary Nebulae Haloes. Planetary Nebulae: Their Evolution and Role in the Universe, Proceedings of the 209th Symposium of the International Astronomical Union held at Canberra, Australia, 19-23 November, 2001. Astronomical Society of the Pacific. p. 447. Bibcode:2003IAUS..209..447C.