I'm not aware of a good discussion of this topic in a book, though one may exist. All reference material I have on the topic is from a few coaches around the country. Occasionally, some good insight into WC-level lines pop up oh blogs from guys like Greg Needell or Harald Harb, and actually Ted Ligety has been pretty open about how his line differs from that of his competition—especially in the years where he was truly dominating GS. As A-man mentioned above, a Google search of rise-line will deliver some good results (some from Needell, I think).
That said, what you’re looking for is much more than a one-size fits all approach. As skill level increases, the line that can be taken varies significantly. The line you would recommend to a 9-year old racer is much different from the line you would work on with a 40-point racer who was trying to break into the 20-point range. Usually, as times improve we tend to see a more direct line—the winning line at an NCAA carnival race is often several meters lower than you’d find at your average U16-18 race where there aren’t a lot of points present—and both differ greatly from the typical winning run at a WC GS. For a young racer, early and higher is better in most cases, and can be adjusted as their skill level improves and they begin to see other, more aggressive lines possible.
One thing that has made people re-think the straighter is faster approach is when Ted came out and started putting multiple seconds on the field of WC GS racers—and was very open about skiing a round line—getting on the new ski as early as possible—to carve more of the turn (though the line Ted considers ‘round’ is still wildly straight by a mere mortal’s standard). The smoother, more round line, where the skis can carve more and carry more speed is faster… sometimes. Other times, the racer who takes the line deeper—timing coming inside until the rise-line or later pulls it off. Complicating the topic even further is watching the lines of Hirscher and Ligety in GS when both are at the top of their game… Very different lines from these two, who are often only separated only by a few tenths of a second.
What ties both approaches together, making them more similar than they are different, is early engagement of the new outside ski—the line is then determined by the timing of pressure—how quickly [or not] it builds and is released. The better your racer becomes at being able to establish early engagement at-will, the more line options will become available as they will have all the time they need to execute the line of their choosing.