\begin{tikzpicture}
  \begin{class}[text width=5cm]{BankAccount}{0,0}
    \attribute{owner : String}
    \attribute{balance : Dollars = 0}

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

  \begin{class}[text width=7cm]{CheckingAccount}{-5,-5}
    \inherit{BankAccount}
    \attribute{insufficientFundsFee : Dollars}

    \operation{processCheck ( checkToProcess : Check )}
    \operation{withdrawal ( amount : Dollars )}
  \end{class}

  \begin{class}[text width=7cm]{SavingsAccount}{5,-5}
    \inherit{BankAccount}
    \attribute{annualInteresRate : Percentage}

    \operation{depositMonthlyInterest ( )}
    \operation{withdrawal ( amount : Dollars )}
  \end{class}

\end{tikzpicture}