To be honest, I don't see a problem with you producing ebooks on subjects you know little about. As you know, a journalist generally speaking is not an expert in any field - we are generalists - but we do ask questions of the experts and the answers are then presented as facts - be it for an article, book or other medium. So, in my opinion, the fact that you are not an expert should not dissuade you from writing ebook. So long as you do solid research and quote the right people who do know. In the long term, as you author books in a specific field, you will be deemed an expert.
There's nothing wrong with making reference to others. In fact, I think it strengthens any book. If you've read mine, you'll know that I do quote or attribute information to various experts. Every chapter starts off with a poignant quote from some industry icon and many are mentioned throughout the book. That doesn't detract from my original work, it enhances it.
I think you'll find the same applies to you. I hope this helps and good luck.