Embed external latex file in org mode

Question

I have an R function which returns a latex fragment, which I'd like to insert into my org file. Here's what I tried, which just inserts the latex source:

#+BEGIN_SRC R :exports none :results silent
data(cars)
fitted <- lm(dist ~ speed, data=cars)
library(stargazer)
stargazer(fitted, out='fitted.tex')
#+END_SRC

#+INCLUDE: "fitted.tex" src latex

The latex output renders fine if I manually paste it into the org file between #+BEGIN_LATEX and #+END_LATEX markers. Here it is for reference:

% Table created by stargazer v.5.2 by Marek Hlavac, Harvard University. E-mail: hlavac at fas.harvard.edu
% Date and time: Wed, Mar 28, 2018 - 04:44:03 PM
\begin{table}[!htbp] \centering 
  \caption{} 
  \label{} 
\begin{tabular}{@{\extracolsep{5pt}}lc} 
\\[-1.8ex]\hline 
\hline \\[-1.8ex] 
 & \multicolumn{1}{c}{\textit{Dependent variable:}} \\ 
\cline{2-2} 
\\[-1.8ex] & dist \\ 
\hline \\[-1.8ex] 
 speed & 3.932$^{***}$ \\ 
  & (0.416) \\ 
  & \\ 
 Constant & $-$17.579$^{**}$ \\ 
  & (6.758) \\ 
  & \\ 
\hline \\[-1.8ex] 
Observations & 50 \\ 
R$^{2}$ & 0.651 \\ 
Adjusted R$^{2}$ & 0.644 \\ 
Residual Std. Error & 15.380 (df = 48) \\ 
F Statistic & 89.567$^{***}$ (df = 1; 48) \\ 
\hline 
\hline \\[-1.8ex] 
\textit{Note:}  & \multicolumn{1}{r}{$^{*}$p$<$0.1; $^{**}$p$<$0.05; $^{***}$p$<$0.01} \\ 
\end{tabular} 
\end{table} 

Answer 1

You should use the export tag instead of the src tag:

#+INCLUDE: "fitted.tex" export latex

Documentation explains almost nothing, so I just tested and it works.

Answer 2

Although it's not necessary for this particular question, I will also add that if you need the code to be inserted into the preamble, then you can use a command such as the following:

#+LaTeX_HEADER: \input{somefile.tex}