42.4 For further reading
For an extensive discussion of the Poincar ́e group, its Lie algebra and repre-
sentations, see [97]. Weinberg [99] (chapter 2) has some discussion of the rep-
resentations of the Poincar ́e group on single-particle state spaces that we have
classified here. Folland [28] (chapter 4.4) and Berndt [9] (chapter 7.5) discuss
the construction of these representations using induced representation methods
(as opposed to the construction as solution spaces of wave equations that we
will use in following chapters).