Skylab: The flown and unflown missions - RocketSTEM
File:Skylab brightness observations of Comet Kohoutek.png - Wikipedia
Con Stoitsis on Twitter: "On this day in 1973 Comet Kohoutek-Skylab became the first comet photographed from space. NASA picture. https://t.co/B7matE7tOT" / Twitter
Skylab | The Space Collective
Our SpaceFlight Heritage: Skylab-4 rises and closes out U.S.' first space station - SpaceFlight Insider
Skylab 1 hi-res stock photography and images - Alamy
File:Comet Kohoutek at perihelion from Skylab with coronagraph.jpg - Wikimedia Commons
Skylab 4
1974 NASA Photo Comet Kohoutek As Seen By Skylab 4 Crew | eBay