They don't have JCR Licklider's talk linked (I've added it to their Disqus comments) but it is actually available here: <a href="https://www.youtube.com/watch?v=SN--t9jXQc0" rel="nofollow">https://www.youtube.com/watch?v=SN--t9jXQc0</a>
The other missing presentation, "The Augmented Knowledge Workshop" by Doug Englebart, is on archive.org: <a href="https://archive.org/details/XD302_86ACM_Prese_AugKnowledgeWorkshopParts1and2" rel="nofollow">https://archive.org/details/XD302_86ACM_Prese_AugKnowledgeWo...</a>