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You mean where you can just type in the name of the book and get an index telling you how easy or difficult it is to read, right? Unfortunately I haven't found an index and have never heard of one. But if I find such a side, I will inform you! If you're looking for a really easy-to-read book-series, I recommend the "Learn German by Stories"-Series. (about level A2) amazon.de/Learn-German-Stories-Berlin-Beginners/dp/1492399493/…
