\begin{tikzpicture}
\begin{axis}[
name=plot1,
axis equal,
axis lines*=middle,
enlargelimits = false, clip=true,
xmin=-3,
xmax=3.5,
ymin=-1.10,
ymax=1.10,
axis line style={->,>=stealth},
xlabel={$\mathrm{Re}\{z\}$},
ylabel={$\mathrm{Im}\{z\}$},
every axis x label/.style={
at={(ticklabel* cs:1)},
anchor=north,
xshift=0.5cm,
},
every axis y label/.style={
at={(ticklabel* cs:1)},
anchor=south,
},
xtick={-3, -0.333, 3, 1}, xticklabels={$-3$, $-\frac{1}{3}$, $3$, 1}, ytick=\empty,
xticklabel style={xshift=0.1cm},
every outer y axis line/.append style={white!15!black},
every y tick label/.append style={font=\color{white!15!black}},
legend style={draw=white!15!black,fill=white,legend cell align=left}]
\draw (axis cs:0,0) circle [black!50, dashed, line width=2pt, radius=1];
\addplot [line width=1pt,mark=x, only marks, mark size = 4pt]
table[row sep=crcr]{
 0 0 \\
 0.333 0 \\
};

\addplot [line width=1pt,mark=*, only marks, mark size = 4pt, mark options={fill=white}]
table[row sep=crcr]{
	-3 0 \\
	3 0 \\
	-0.3333 0\\
};
\node[above, anchor=south west] at (axis cs: 0, 0) {$2$};
\end{axis}

\begin{axis}[
name=plot2,
at= (plot1.south west), anchor=north east, xshift=3cm, yshift=-1cm,
%at=(plot1.below south east), anchor=above north east,
axis equal,
axis lines*=middle,
enlargelimits = false, clip=true,
xmin=-3,
xmax=1.5,
ymin=-1.10,
ymax=1.10,
axis line style={->,>=stealth},
xlabel={$\mathrm{Re}\{z\}$},
ylabel={$\mathrm{Im}\{z\}$},
every axis x label/.style={
	at={(ticklabel* cs:1)},
	anchor=north,
	xshift=0.5cm,
},
every axis y label/.style={
	at={(ticklabel* cs:1)},
	anchor=south,
},
xtick={-3, -0.333, 1}, xticklabels={$-3$, $-\frac{1}{3}$, $1$}, ytick=\empty,
xticklabel style={xshift=0.1cm},
every outer y axis line/.append style={white!15!black},
every y tick label/.append style={font=\color{white!15!black}},
legend style={draw=white!15!black,fill=white,legend cell align=left}]
\draw (axis cs:0,0) circle [black!50, dashed, line width=2pt, radius=1];
\addplot [line width=1pt,mark=x, only marks, mark size = 4pt]
table[row sep=crcr]{
	 0 0 \\
};

\addplot [line width=1pt,mark=*, only marks, mark size = 4pt, mark options={fill=white}]
table[row sep=crcr]{
	-0.333 0 \\
	-3 0 \\
};
\node[above, anchor=south west] at (axis cs: 0, 0) {$2$};
\end{axis}

\begin{axis}[
name=plot3,
at= (plot2.east), anchor=west, xshift=1cm,
%at=(plot2.below south east), anchor=above north east,
axis equal,
axis lines*=middle,
enlargelimits = false, clip=true,
xmin=-1,
xmax=3.5,
ymin=-1.10,
ymax=1.10,
axis line style={->,>=stealth},
xlabel={$\mathrm{Re}\{z\}$},
ylabel={$\mathrm{Im}\{z\}$},
every axis x label/.style={
	at={(ticklabel* cs:1)},
	anchor=north,
	xshift=0.5cm,
},
every axis y label/.style={
	at={(ticklabel* cs:1)},
	anchor=south,
},
xtick={0.333, 3, 1}, xticklabels={$\frac{1}{3}$, $3$, 1}, ytick=\empty,
xticklabel style={xshift=0.1cm},
every outer y axis line/.append style={white!15!black},
every y tick label/.append style={font=\color{white!15!black}},
legend style={draw=white!15!black,fill=white,legend cell align=left}]
\draw (axis cs:0,0) circle [black!50, dashed, line width=2pt, radius=1];
\addplot [line width=1pt,mark=x, only marks, mark size = 4pt]
table[row sep=crcr]{
	0.333 0 \\
};

\addplot [line width=1pt,mark=*, only marks, mark size = 4pt, mark options={fill=white}]
table[row sep=crcr]{
	3 0 \\
};
\end{axis}
\node[black, fill=black!10, minimum width=1cm, align=center] at ($(plot1.north east)+(0.2cm,0)$) {\Large $H(z)$};
\node[black, fill=black!10, minimum width=1cm, align=center] at ($(plot2.north east)+(0.2cm,0)$) {\Large $H_{lin}(z)$};
\node[black, fill=black!10, minimum width=1cm, align=center] at ($(plot3.north east)+(0.2cm,0)$) {\Large $H_{ap}(z)$};

\end{tikzpicture}