Digital Transformation of Signatures: Suggesting Functional Symmetry Approach for Loan Agreements oleh Viktor Titov, Pavel Shust, Victor Dostov, Anna Leonova, Svetlana Krivoruchko, Nadezhda Lvova, Iurii Guzov, Angelina Vashchuk, Natalia Pokrovskaia, Anton Braginets, Mikhail Zaboev