\begin{tikzpicture}
 % \draw[help lines] (-7,-6) grid (6,0);

 \begin{class}[text width=6cm]{OverdrawnAccountsReport}{0,0}
   \attribute{generatedOn : Date}

   \operation{refresh ( )}
 \end{class}

 \begin{class}{BankAccount}{12,0}
   \attribute{owner : String}
   \attribute{balance : Dollars}

   \operation{deposit(amount : Dollars)}
   \operation[0]{withdrawl(amount : Dollars)}
 \end{class}

 \unidirectionalAssociation{OverdrawnAccountsReport}{overdrawnAccounts}{0..*}{BankAccount}

\end{tikzpicture}