Citation guides assume one is engaged in contemporaneous research and has the luxury of fully documenting one's sources. But in the real world research foci shift over time and a passing reference or hallway conversation at a conference can take on a new relevance long after the book being read has been re-shelved or the identity of the passing acquaintance who mentioned some nugget of historical interest has been long forgotten. The safe answer from a plagiarism avoidance perspective is to excise the idea and any fruits from the poisonous tree from one's writing, but this seems like the wrong result from a preservation and advancement of knowledge perspective, since it would prevent the idea from being shared, block one's own research from progressing in its direction, and foreclose the possibility of someone reading whatever context one can now recall from reaching out to provide the proper citation. Do any citation systems address this issue and provide a mechanism to flesh out as much context as one can remember, as in "I am certain that either a grad student or junior researcher in industry at a conference in Pittsburg (which I am fairly confident was related to programming languages and held in the late 1990's) told me he had learned that a certain programming languages tooling project was re-branded as robotics research to pursue defense funding"