PDP-7 booting UNIXv0:
https://youtu.be/pvaPaWyiuLA
AT&T Archives, The UNIX OS:
https://youtu.be/tc4ROCJYbm0
GNU website:
https://www.gnu.org/home.en.html
FSF website:
https://www.fsf.org/it
How to pronounce Linux:
https://mirrors.edge.kernel.org/pub/linux/kernel/SillySounds/
Mail Thread Linux announcement:
https://groups.google.com/g/comp.os.minix/c/dlNtH7RRrGA/m/SwRavCzVE7gJ
TOP500 Super computers list: 
https://top500.org/statistics/list/}{Vedi TOP500 OS Family
W3 statistics about OS adoption in web servers:
https://w3techs.com/technologies/overview/operating_system
MARCONI webpage:
https://www.hpc.cineca.it/hardware/marconi
INDACO website:
https://www.indaco.unimi.it/
LCM Farm webpage:
https://lcm.mi.infn.it/farm/
Teletype video:
https://www.youtube.com/watch?v=9TGQ4pnVWSQ
