Doctor Lesko's notes is a holotape in Fallout 3.
Location[]
This holodisk is added to the Lone Wanderer's Pip-Boy after reading the "Sample Location Discovered!" entry on either Lesko's terminal in the recently built shack or Marigold station lab.
Transcript[]
Sample Location Discovered!
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I've found the perfect specimen for my experiments inside Marigold Station! I've set up shop underground for now while I prepare the experiment. All I need is a bit of last-minute programming on my robot and it will be ready to perform the delicate injections. Soon I will prove to everyone that my formula is a viable alternative to the destruction of these misunderstood beings.