Article 30 [Prohibition of New Customs Duties or Charges Having Equivalent Effect]Kerikmäe, Tanel; Särav, SandraTreaty on the Functioning of the European Union - A Commentary2021 / p. 711-718 https://doi.org/10.1007/978-3-030-43511-0_31

Article 31 [Common Customs Tariff]Kerikmäe, Tanel; Särav, SandraTreaty on the Functioning of the European Union - A Commentary2021 https://eproofing.springer.com/books_v2/mainpage.php?token=odTi5FgswcHBIhji8RIrYBWaxAw9x_0CxK-8rEWmY5Y https://doi.org/10.1007/978-3-030-43511-0

Article 32 [Principles for Commission Duties]Kerikmäe, Tanel; Särav, SandraTreaty on the Functioning of the European Union - A Commentary2021 https://eproofing.springer.com/books_v2/mainpage.php?token=odTi5FgswcHBIhji8RIrYBWaxAw9x_0CxK-8rEWmY5Y https://doi.org/10.1007/978-3-030-43511-0_33

Article 33 [Customs Cooperation]Kerikmäe, Tanel; Särav, Sandra; Hamulak, OndrejTreaty on the Functioning of the European Union - A Commentary2021 / p. 733-736 https://doi.org/10.1007/978-3-030-43511-0_34