3. Pay the first invoice,

which is 50% of the total registration fee, before 30 April 2012

The invoice should be paid at the latest on 30 April to confirm the pre-booking at early rate. In case you made the reservation on 30 April, the first invoice should be paid before 10 May (within 10 days).
After payment of the first invoice, the number of pre-booked registrations will stay blocked at the early fee until the Group Registration Form is sent in at the latest on 27 May 2012. All Group Registration Forms sent in after this deadline, will be processed at the late fee.

Read more about the payment conditions