Text is not fitting the column

Question

I want my texts to continue in the next line instead of continuing in the other column. How can I manage this? My code is : ![enter image description here][1]

\begin{tabular}{|p{2,8cm}|p{2.8cm}|p{2.8cm}|p{2.8cm}|p{2.8cm}|}
  \hline
  \textbf{Architecture }& \textbf{Sharing }& \textbf{TrustSetting} & \multicolumn{2}{l|}{\textbf{Access Control}}\\ \hline
  Distributed:\cite{ 40crossdomain},\cite{51cassandra},\cite{53oasis},\cite{54huDynamic},\cite{79searchengine},\cite{19paas} &    & Trusted: & \textbf{Cryptographic }& \textbf{Non-cryptographic} \\ \cline{4-5}
    &   &  &  &  \\ 
   &    &  &  & \\\cline{1-1}\cline{3-4}
  Centralized: &    & Semi-trusted: &  &  \\\cline{2-2}
   &    &  & &  \\ 
   &   &  &  &  \\\cline{1-1}\cline{3-4}
  Cloud: &    & Untrusted: &  & \\
   &   & &   &   \\ \hline

\end{tabular}

Answer 1

If you insert a space between Distributed: and the series of \cite commands, you'll allow LaTeX to insert a line break. The ? marks in the screenshot below arise because I can't resolve the \cite instructions. If need be, insert another space between some of the \cite commands in order to allow still another line break.

![enter image description here][1]

\documentclass{article}
\begin{document}
\noindent
\begin{tabular}{|p{2.8cm}|p{2.8cm}|p{2.8cm}|p{2.8cm}|p{2.8cm}|}
\hline
\textbf{Architecture }& \textbf{Sharing }& \textbf{TrustSetting} & 
\multicolumn{2}{l|}{\textbf{Access Control}}\\ 
\hline % Observe the space after "Distributed" in the next line
Distributed:,\cite{19paas} &    
& Trusted: & \textbf{Cryptographic }& \textbf{Non-cryptographic} \\ 
\cline{4-5}
    &   &  &  &  \\ 
    &   &  &  & \\
\cline{1-1}\cline{3-4}
Centralized: &    & Semi-trusted: &  &  \\
\cline{2-2}
   &    &  & &  \\ 
   &   &  &  &  \\
\cline{1-1}\cline{3-4}
Cloud: &    & Untrusted: &  & \\
   &   & &   &   \\ 
\hline
\end{tabular}
\end{document}

Incidentally, instead of six separate \cite instructions, you could provide a single \cite command that takes six arguments:

\cite{40crossdomain,51cassandra,53oasis,54huDynamic,79searchengine,19paas}

This will allow LaTeX to insert a line break automatically.

---

Addendum: The OP has deleted some of the LaTeX code as well as the screeshot I posted.