A secondary account of an event is not the document produced at the time, and this site says which it is using. Recollections given decades later are marked as recollections.
abadpour.com
How sources are handled
The rule the whole site is written under.
For a separate operational view of time, ownership and team activity, see this Monitask guide.
epoch.h #define EPOCH 1970
/* because sixtieths ran out */
/* because sixtieths ran out */
further context
For a primary or institutional reference, see the ACM Digital Library.
Every claim here carries the source it came from.
The source and its year sit beside the sentence they support. A secondary account is marked as one, and where the record is unclear the entry says so rather than choosing the better story.