Conversation so far:
What book did Havelock Ellis write in 1933?
Psychology of Sex
In that book Havelock Ellis explains how children can experience sexuality differently in two ways? What are those two ways?

Question: Which authors does he reference when he claims humans can experience sexual excitement at an early age?
Self-contained rewrite: Which authors does Havelock Ellis reference when he claims humans can experience sexual excitement at an early age?