Initially, you might think the idea of taking freely available information (i.e. articles from a directory that is free to browse) and bundling them into a book isn't exactly the brightest product-creation strategy in the world; however, in order to think that, you'd have to ignore how well repackaged anthologies and classics volumes have sold over the course of decades.
Indeed, repackaging, aggregating, and/or putting your own “twist” on something that already exists does add value that customers are willing to pay for. People who buy your product may technically have access to all of those sources, but if they don't know they exist – or
if they don't want to sift through the internet to find the few gems – then you have provided a helpful service: you have conducted the research and have compiled high-quality information for them.
Repackaging articles is a completely legitimate and effective way to make products. In fact, if you look at a number of successful book series, such as Chicken Soup for the Soul, they're repackaged stories/talks that were submitted to an editorial board. The editors simply put their spin on the stories by creating an introduction, conclusion, and theme (for each book).
There's only one important caveat to keep in mind (and keeping it in mind will make the product-creation process easier): you cannot legally use articles from directories to create products unless you solicit the permission from their authors.
Simply, find the articles that fit your theme and email each of the authors asking if you can use their material in one of your upcoming products. Tell them you will place their respective resource boxes in your book, so that they receive credit for their articles.
Some authors will respond quickly to your email. Others will ignore it. Rather than waiting on the slow responders and non-responders, go with the authors who respond quickly.
In total, you will probably want to select between 10 and 30 articles for your book, since each article will run about 300-400 words, which will take up only slightly more than one page.