Some of those &quot;month unknown&quot; are easily filled out, like this one for example:<p><i>(month unknown) Motorola introduces its 6800 chip</i><p><a href="https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Motorola_6800#M6800_family_introduction" rel="nofollow">https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Motorola_6800#M6800_family_int...</a><p><i>The first working MC6800 chips were produced in February 1974</i><p>The references on the site consist mostly of magazines and are noticeably absent of any manufacturer&#x27;s databooks&#x2F;datasheets, which I&#x27;d consider looking at first before anything else.