Gaps in the Literature

One of the main points of an annotated bibliography is to IDENTIFY THE GAPS in the literature. What are the issues which have not been researched already? Quite often the open questions in the field will be discussed in the literature by various authors. For example, Camerer in his book on Behavioral Economics explains that there have been too many experiments on the Ultimatum Game and no more are needed, instead one should work on such and such. In the last chapter of his book he mention TEN most important open questions on which there has been very little research.