\subfloat 错误

Question

我在网上检查了很多次，但仍然找不到错误。如果能得到任何帮助，我将不胜感激。

\documentclass[12pt,letter]{article}
\usepackage{fullpage}
\usepackage{setspace}
\usepackage{parskip}
\usepackage{titlesec}
\usepackage{caption}
\usepackage{epstopdf}
\usepackage{subfig}
\usepackage{graphicx}
\usepackage{float}
\usepackage{wrapfig}

\begin{document}

\begin{figure}
        \centering
  \subfloat[Argentina]{\includegraphics[scale=0.5]{GCF_ARG}}
  \subfloat[Brasil]{\includegraphics[scale=0.5]{GCF_BRA}}\\
  \subfloat[M\'exico]{\includegraphics[scale=0.5]{GCF_MEX}}
  \subfloat[China]{\includegraphics[scale=0.5]{GCF_CHN}}\\
   \subfloat[India]{\includegraphics[scale=0.5]{GCF_IND}}
  \subfloat[Rusia]{\includegraphics[scale=0.5]{GCF_RUS}}\\
   \subfloat[Sudafrica]{\includegraphics[scale=0.5]{GCF_ZAF}}
  \subfloat[USA]{\includegraphics[scale=0.5]{GCF_USA}}\\
  \subfloat[Indonesia]{\includegraphics[scale=0.5]{GCF_IDN}}
  \subfloat[Turqu\'ia]{\label{fig:tur}\includegraphics[scale=0.5]{GCF_TUR}}\\
 \caption{Ciclos econ\'omicos de Formaci\'on Bruta de Capital (GCF)}
  \label{rbc1}
\end{figure}

\end{document}

我收到错误！未定义控制序列。l.316 \subfloat [阿根廷]{\includegraphics[scale=0.5]{GCF_ARG}}？

谢谢。