I would like also to politely say that this book is definitely reliable as in it each piece of info is referenced with the episode from which it comes Moreover it is a very popular book among whofans to whom the slightest error would be noticeable and it is a culmination of over a decades research on this subject hope this clears the matter up for you  though your point was definitely valid and I am glad to see that such things are checked Thanks for justifying my source  very kind of you Sorry I didnt reply sooner