Bibcode
                                    
                            Corradi, Romano L. M.; Aznar, Regina; Mampaso, Antonio
    Bibliographical reference
                                    Monthly Notices of the Royal Astronomical Society, Volume 297, Issue 2, pp. 617-623.
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                        6
            
                        1998
            
  Citations
                                    42
                            Refereed citations
                                    34
                            Description
                                    Narrow-band CCD images of 209 axially symmetrical planetary nebulae
(PNe) have been examined in order to determine the orientation of their
axes within the disc of the Galaxy. The nebulae have been divided into
the bipolar (B) and elliptical (E) PNe morphological types, according to
the scheme of Corradi & Schwarz. In both classes, contrary to the
results of Melnick & Harwit and Phillips we do not find any strong
evidence for non-random orientations of the nebulae in the Galaxy.
Compared with previous work in this field, the present study takes
advantage of the use of larger and morphologically more homogeneous
samples and offers a more rigorous statistical analysis.