In a superb course in astrono
my, Phil Plait lectures in a series of tens of 12-minutes long episodes on all topics of astronomy. In episode #30, White Dwarfs & Planetary Nebulae: Crash Course Astronomy #30, he mentions (7:20 minutes) my idea that many planetary nebulae might be shaped by planets.
Phil Plait was my master student (University of Virginia, 1990), and we studied the planetary nebula NGC 6826 seen here.