This image was acquired from
wikimedia. It was marked as Public Domain or CC0 and is free to use. To verify, go to the source and check the information there.
Sky Lab Issuec. US Postage stamp issue SkyLab Commemorative US Post Office Gwillhickers Image obtained from hires scan of US Postage stamp from private collection US Post Office PDUSGov History of the United States on stamps Skylab program Commemorative stamps of the United States
Page 2023 Free-images.com. All images are Public Domain