documentclass{article}
usepackage{tikz}

usetikzlibrary{arrows,automata}

begin{document}
begin{tikzpicture}[narray/.style={circle,fill=white,draw},node distance=3cm,
                norm/.style={circle,fill=black,draw,minimum size=0.2cm}]

  node[narray] (q1) {tikzdraw[black, fill=black] (0,0) circle (.7ex);} ;
  node[norm] (p1) [right of=q1] {};

  path
    (q1) edge [->,>=latex',thick] node[above] {A} (p1);
end{tikzpicture}
end{document}

documentclass{article}
usepackage{tikz}
usetikzlibrary{arrows,petri,positioning,decorations.markings}

begin{document}

begin{tikzpicture}[
  node distance=3cm,
  norm/.style={
    circle,
    fill=black,
    draw,
    minimum size=0.2cm
  },
  >= latex
]

node[place,tokens=1,label={80:$n$}] (p1) {} ;
node[norm,below right=of p1] (q1) {};
node[place,tokens=1,above right=of q1,label={80:$m$}] (p2) {} ;

draw[->]
    (p1) --
    (p2)
    node[pos=0.15,above] {$[2..3]$}
    node[pos=0.85,above] {$[1..2]$}
    ;
draw[->]
    (p1) --
    (q1)
    node[pos=0.05,below=6pt] {$[4]$}
    node[midway,draw,fill=white] {$t$}
    ;
begin{scope}[decoration={
    markings,
    mark=at position 0.15 with {arrow{>}},
    mark=at position 0.9 with {arrow{<}}
    }
  ]
  draw[-,postaction=decorate]
    (p2) --
    (q1)
    ;
end{scope}
end{tikzpicture}

end{document}

node[pos=<value>,<position>] {text}