In countries such as Russia and China, where copyright laws are more lenient or less well enforced, it is not uncommon to see fan fiction based on the work of popular authors published in book form. Sergey Lukyanenko, a popular science fiction author, went as far as to incorporate some fan fiction based on his stories into official canon (with permission of the writers of the said fan fiction). Perhaps the most famous case, however, is Dmitri Yemets' "Tanya Grotter" book series, a "cultural response" to "Harry Potter", which provoked a lawsuit from J. K. Rowling.