I did some research in the 80s and discovered a scientific report in one of the World Health Organization (WHO) volumes from the early 70s that was a research paper on a man-made virus that attacks T-cells. At the end of the report there was a discussion of what the next steps were going to be and it stated that Black men in New York City would be given 'shots' with this new virus and that the results would be monitored. New York is where AIDS first appeared in the early 80s amongst homosexual black men.
When I discovered this research paper I had it photocopied and even had the green slip of paper that logged where it was in the British Library. I carried this paperwork around with me wherever I moved to for over 10 years. I then lent it out to an organization for them to look at. I never got it back from them as it 'disappeared'.
When I went back to the British Library in March 2017 I spent two days going through all the WHO volumes and found that the volume that had contained this research paper had disappeared.
Even the magazine that I had got the reference from of where to find this data had entirely disappeared from the archives of the library -p the entire set of magazines could no longer be found.
Now, all that I have is a memory of what I had discovered. That really sucks.