When you only have partial information about a source, which is not enough to guide an audience member to the source on their own, you can

Multiple Choice

use the source and cite what information you do have about it$.$

only use the source if you track down the details you are missing and give a good citation.

use the evidence without citing its source.

use the source by citing what information you do have, but you must apologize to the audience for its being incomplete.