1. Open your EndNote library.  Using the ctrl key, or the ctrl and shift keys, select references that you want to export. 
2. The first time you do this, you will need to add the BibTeX export style to your list of options. 
3. Go to Tools, then Output Styles, then Open Style Manager.

    

   

 

4. Find and select BibTeX Export in the alphabetical style options  

    

   

 

5. Close the Output Styles window. 
6. Go back to Tools, Output Styles, and Select BibTeX Export

    

   .

 

7. Use the ctrl key, or the ctrl key combined with the shift keys, select references that you want to export. 
8. Go to File and then Export. 
9. Choose where you want to save your file. 
10. Select Text File (*.txt) from the file type dropdown menu
11. Save your file as filename.bib
12. Note: BibTex entries exported from EndNote do not have a BibTex Key. You will need to create a key for each entry.

In EndNote Basic you export a group of references rather than individual references.  

1. To create a group, click on Organize in the menu bar, then select New group to create and name the group.
2. Next, go to My References in the menu bar.  Select all the references to be added to the group by ticking the box next to each, then using the Add to group pulldown menu to choose a group. 
3. Next select Format in the menu bar. 
4. Choose Export References.
5. Select the group of reference to export. 
6. For export style, select BiBTeX Export.
7. Click Save.  

The file will be saved as a .txt file. Copy and paste the contents into a .bib file, in, for example, in a LaTeX file in Overleaf.