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I have been playing with the project and noticed that something strange. Sources that are in the first file that I have included in master.tex appear as they should, but they don't work in the other files. I have copied the exact same text (shown below) into the first file and the source works there ...

Thank you for getting back to me. Included below is one of the documents that is included in the master posted above. Note in the second to last paragraph there are several sources that were posted to test. When compiled in Overleaf they appear as follows: [?] [1] [?] [?][?] [2] [?]. In addition ...

I'm working on a project and some of my sources are showing up as question marks. I can't figure out what the problem is. I've tried copying the format of the sources that work, inputting different information, and calling them something else, but they then show up as question marks. It seems to be ...