you do actual measurements to see what factor the ambient temperature has on the measured temperature of a phone battery? How about having the phone touch a 37 degrees centigrade heat bath on one side (in other words: a human body) and ambient air on the other? Before this paper, could you have made any reliable prediction on how big an influence ambient temperatures were on the sensors in the battery?

There are mechanical engineering textbooks on the subject, such as http://books.google.ca/books?id=vvyIoXEywMoC&hl=en. Reliable heat transfer analysis has existed long before this paper was released.