Hello friends, I am myself learning German and I am proud to announce that my mom, who completed her masters in German, has published her book called "German Grammar Guide" on amazon kindle platform. She has had a lot of training and teaching experience and I can assure that this book will really prove to be very useful for anyone learning German. It has been presented in a very easy to understand language. Do check it out on the given link and please spread the word:
https://www.amazon.in/German-Grammar-Guide-Pooja-Dhamale-ebook/dp/B01M34368Z?ie=UTF8&keywords=german grammar&qid=1480268347&ref_=sr_1_6&s=books&sr=1-6