https://www.rbth.com/history/330415-last-soviet-citizen-cosmonaut#:~:text=The%20last%20Soviet%20citizen%3A%20The%20cosmonaut%20who%20was%20left%20behind%20in%20space,-History&text=Sergei%20Krikalev%20was%20in%20space,than%20originally%20planned%20in%20orbit.
https://www.discovermagazine.com/the-sciences/the-last-soviet-citizen
https://www.space.com/11337-human-spaceflight-records-50th-anniversary.html#:~:text=Most%20consecutive%20days%20in%20space,when%20he%20finally%20touched%20down.
https://www.esa.int/Science_Exploration/Human_and_Robotic_Exploration/Eneide_-_Vittori_mission/Sergei_Konstantinovich_Krikalev
https://www.history.com/this-day-in-history/coup-attempt-against-gorbachev-collapses