Identifying new references when appending to existing reference list I am building a database from several online sources like Engineering Village. Everyday I am searching different/close/related keywords that pertains to my research topic. Then, I am (everyday) exporting and printing out the documents to do manual filtering depending on the relevance of the article/report. I also importing/appending daily search results into my cumulative list. This may lead to duplication which Reference Managers identifies and filters out in most cases. How do I have a daily reference list such that there is no duplicates? In order words, is there a way to know each time I append my references which are the new ones that I generated (through query) only today.

Please let me know if you need any clarifications. Thank you for your help.
If you are using the EndNote reference manager, it will tell you that you are importing duplicates, which references are duplicates, and then give you options for what you can do with them. It seems reasonable that other reference managers will do the same.

As an example, many journals now have adopted the practice of publishing articles online before they have been assigned to a print volume. Thus, I may want the manager to replace the old reference (without page and volume information) with the new (with that information). EndNote lets me choose to do this.