The abbreviation qtd. in, when used in a citation, stands for “quoted in”, and is used when quoting from a secondary source. As with many abbreviations, the full stop at the end of qtd is optional.

Simone de Beauvoir’s famous words “one is not born a woman; one becomes one” (qtd in Moi, Sexual/Texual… 92) formed the starting point for second-wave feminism.