The articles she wrote are all so relevant to bridge learners and explain some important principles and methods. Here is a short extract from her article about responding at the two level.
"Responding at the two level - It is amazing how the smallest details can cause the most heated discussions. One such topic is how many high card points are needed to make a change of suit response at the two level. We know that when partner opens the bidding with a one level bid, the range of strength is between 12 and 19 points. We also know that we should respond to that opening bid with six points, just in case partner has 19 and we have the magic 25 points between the two hands – enough to bid to game. A response at the one level is very wide ranging – from 6 to 16 or more points – it is just the first move in an auction to be held about what should be the final contract."
Click here to see the full article with example hands