If you are not finding it, it’s not that you aren’t looking hard enough. It’s more likely that it’s just not there. So say your core offer is articles. If articles are important in your niche, you would see evidence of this. Your potential clients would be publishing them because they would want people to be reading them. They should be easy to find. If this is the case, then you may need to decide if your core offer is more important or your niche is more important. If the type of writing you offer is what you want to focus on then you may have to change your niche. If your niche is more important then you may want to change your core offer to something that is widely used in that industry.