From the site:
Collca is an electronic publisher specialising in non-fiction bitesize ebooks for popular ereading devices such as Amazon’s Kindle, Apple’s iPad, Barnes & Noble’s Nook and Kobo’s eponymous ereader. We cover a wide range of subjects including biography, health, reference, sport and travel. Our titles are available from hundreds of popular ebook retailers all around the world. We also publish a number of apps for Apple’s iPad, iPhone and iPod Touch devices.