Checking/syncing references across 15 papers

Hello!

I am helping compile a supplement of 15 research papers. Each of these papers is written by different authors, who wrote their manuscripts using Microsoft Word but used different referencing software/libraries. There are some references that are cited in all the papers but may appear different due to whoever input the information. For example, all 15 papers cite a particular protocol - I need to ensure such sources are cited correctly and consistently in each individual paper. I will have access to everyone’s manuscripts and referencing files. 

What is the best way to do this without having to manually change each citation one by one for every paper? Is it possible to have all the references merged into 1 big library and somehow sync all the shared citations across 15 papers? Thank you.

Before I think about a solution, I need to know what referencing style was used in each so are they numbered, and ordered by appearance   or numbered alphabetically  or author year. 

If numbered - will they need to share the numbering system of be stand alone?  

Does it end up in one long bibliography or you are doing each one with a separate bibliography?  

How hard would it be to get all the cited articles in one library?  Do you have access to a database to download them from, so they are consistent in that respect?  

How many different referencing software packages were used, and do you have access to them

(and what were they?) 

Hi Leanne,

Thank you for your reply. 

The references are numbered in order of appearance and there is a separate bibliography for each paper. They are stand alone, not shared. The authors are part of our collaborative team – we could ask them to “export” the EndNote group for their paper and send to us.   Authors have each used their individual EndNote libraries (one has used Zotero).