1. Member States may deduct periods of theoretical instruction in the fields referred to in Article 6 from the years of professional activity referred to in Article 9, provided that such instruction is attested by an examination recognized by the State. Such instruction must last not less than one year, nor may it reduce the period of professional activity by more than four years.
2. The period of professional activity as well as the practical training must not be shorter than the programme of theoretical instruction and the practical training required by Article 4.