There are many books by Kesar Lall most of which are very difficult to source in the UK (and expensive to ship – beware.) However I have found an amazing list of his books located around the world here. If you are very serious about learning all there is about Nepalese fairy tales then this is a great resource.
Folk Tales from the Kingdom of Nepal
Folk tales from the Himalayan Kingdom of Nepal. The crooked tree and other tales.
Folk tales from the Himalayan Kingdom of Nepal. The Stolen image and other stories.