English: Figure 6-2. Changes in upper and lower limb volumes obtained by circumference measurements of 3-cm segments in the three crewmembers from Skylab 4. It should be noted that, because of a much higher exercise volume in the Skylab 4 crewmembers, their loss of muscle volume was much less than observed in crewmembers from Skylab 2 and 3. From reference. [§ 1]:pages
The NASA website hosts a large number of images from the Soviet/Russian space agency, and other non-American space agencies. These are not necessarily in the public domain.
The SOHO (ESA & NASA) joint project implies that all materials created by its probe are copyrighted and require permission for commercial non-educational use. [2]