Shifted Quote environment

Question

By some weird standards I need to create a quote environment following some strict rules. (as we can see in attached figure)

While the document uses 1.5 spacing the quotation should use regular (1) spacing. Be 2.5cm shifted to right (the whole paragraph) and use smaller fontsize.

Right now I'm using lualatex and I use setspace package to set document line spacing with the command \onehalfspacing. I tried many things but was not able to get this working. Hence I came here to ask you how to accomplish that.

Answer 1

This is very easy with the quoting package and its eponymous environment:

\documentclass{book}
\usepackage[utf8]{inputenc}%
\usepackage[T1]{fontenc} %
\usepackage{setspace} %
 \usepackage{quoting} %
\usepackage{lipsum}
\quotingsetup{font={footnotesize, noindent}, leftmargin=2.5cm, rightmargin=0cm}

 \begin{document}

\onehalfspacing

 \lipsum[2]

\begin{singlespacing}
    \begin{quoting}[]
    Sed feugiat. Cum sociis natoque penatibus et magnis dis parturient
     montes, nascetur ridiculus mus. Ut pellentesque augue sed urna.
     Vestibulum diam eros, fringilla et, consectetuer eu, nonummy id,
     sapien. Nullam at lectus. In sagittis ultrices mauris. Curabitur
     malesuada erat sit amet massa. Fusce blandit. Aliquam erat volutpat.
     Aliquam euismod. Aenean vel lectus. Nunc imperdiet justo nec dolor.
    \end{quoting}
\end{singlespacing}
\lipsum[3]

\end{document} 

Answer 2

Here is an adapted version of one of my previous answers:

\documentclass{article}
\usepackage{setspace}
\usepackage{lipsum}

\onehalfspacing

\usepackage{changepage}
\newenvironment{myquote}{\par\vspace{\baselineskip}\begin{singlespace*}\begin{adjustwidth}{2.5cm}{0cm}\small}{\end{adjustwidth}\end{singlespace*}\par\vspace{\baselineskip}}


\begin{document}

\lipsum[1]

\begin{myquote}
\lipsum[5]
\end{myquote}

\lipsum[1]
\end{document}

Answer 3

You can use xparse to define the new environment.

I also used biblatex to get more flexibility in typesetting citations.

\begin{filecontents*}{\jobname.bib}
@article{oliveira1995,
  author={Oliveira, X.},
  title={whatever},
  year={1995},
}
@article{levi-strauss1970,
  author={Levi-Strauss, A. and Xyz, X. and Abc, Y. and Somebody, S.},
  title={whatever},
  year=1970,
}
@article{laraia2006,
  author={Laraia, L.},
  title={whatever},
  year=2006,
}
\end{filecontents*}

\documentclass[a4paper]{book}
\usepackage[margin=2.75cm]{geometry}
\usepackage[T1]{fontenc}
\usepackage[brazilian]{babel}
\usepackage[style=authoryear]{biblatex}
\usepackage{csquotes}
\usepackage{xparse}
\usepackage{setspace}

\addbibresource{\jobname.bib}
\renewcommand*{\mkbibnamefamily}[1]{\MakeUppercase{#1}}

\NewDocumentEnvironment{squote}{omb}
 {%
  \list{}{
    \setlength{\leftmargin}{2.5cm}%
    \setlength{\rightmargin}{0pt}%
  }%
  \singlespacing\small\item\relax \enquote{#3}
  \IfNoValueTF{#1}{%
    \parencite{#2}%
  }{%
    \parencite[#1]{#2}%
  }%
  \endlist
 }{}

\onehalfspacing

\begin{document}

Conforme \textcite[30]{oliveira1995} relativizar é constituinte do próprio 
conhecimento antropológico. Sendo relativizar uma atitude epistêmica,
eminentemente antropológica, em que o pesquisado busca fugir do etnocentrismo. 
\begin{squote}[239]{levi-strauss1970}
A noção de evolução biológica corresponde a uma hipótese dotada de um dos mais altos 
coeficientes de probabilidade gue podem encontrar-se no dominio das ciências naturais; 
ao passo que o conceito de evolução social ou cultural só conduz: no máximo: a um 
procedimento sedutor, mas perigosamente cómodo: de apresentação dos fatos.
\end{squote}

Este trecho de \textcite{levi-strauss1970} nos ajuda compreender o que 
\textcite[93]{laraia2006} diz sobre a lógica de um sistema cultural depende 
da compreensão das categorias constituídas pelo mesmo \parencite[93]{laraia2006}.

\end{document}