Young Planetary Nebulae: Hubble Space Telescope Imaging and a New Morphological Classification System - Sahai, Raghvendra; Morris, Mark R; Villar, Gregory G (The Astronomical journal, 2011)
Keywords: ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; CLASSIFICATION; IMAGE PROCESSING; IONIZATION; NEBULAE; PHOTOIONIZATION; PLANETARY NEBULAE; PROCESSING; STARS; TELESCOPES