We know we don't have everything and therefore I have decided to share with you books I have read myself that I can recommend.
BI Requirements Gathering
For many companies this is complex, time consuming and can lead to either efficient delivery or money wasting delivery.
Requirements Gathering is actually quite simple. All you need is an experienced BI Analyst and Data Modeler (sometimes one person) who knows how to use BEAM: Business Events Analysis & Modeling (similar to Kimball Enterprise Bus Matrix, but business friendly edition)