public function toArray()
    {
        $array = array(
            'firstName'   => $this->firstName,
            'lastName'    => $this->lastName,
            'email'       => $this->email,
            'telephone'   => $this->phoneNumber,
            'mobile'      => $this->mobileNumber,
            'companyName' => $this->companyName,
        );
        if ($this->address !== null) {
            $array['address'] = $this->address->toArray();
        }

        return $array;
    }