Transfer iBook to Nook

Both of my daughters have Nooks and we wanted to see if it were possible to transfer books downloaded from iBook to the Nook. I found a few old articles, but the most recent information I found for Mavericks was here http://ebookconverter.blogspot.com/2013/11/where-to-find-epub-file-in-ibooks-for.html. The salient points:

1. books are under ~/Library/Containers/com.apple.BKAgentService/Data/Documents/iBooks/Books

2. epub folder can be converted to a epub file by zipping up the contents and changing the extension from zip to epub. Don’t zip up the folder; e.g.  ”43345345.epub”,  rather, open that folder and select all the files and compress those.