# Page 137

**Location:** Chapter 13, solution to Problem 7

## It is (second paragraph)

If in the above expression we take \(BC\) for \(Q\), we get ...

## It should become

If in the above expression we take \(CB\) for \(Q\), we get ...

## Short explanation

One sees immediately, by substitution, that the right expression to construct a Queer bird is the latter.