Acknowledgements Manager and co-ordinator Barbara Moauro Consultants, translators, technical authors and data input and update Mogir Alahmad, Valentina Behara, Clara Bosco, Dora Egri, Romina Faragasso, Elfi de Franchis, Vsevolod Gnetii, Ruud Hupperts, Eylul Kocer, Mishael Levron, Yota Nicolarea, Peter Pusara, Eloy Sánchez, Ann Camilla Scott, Monica Simone, Alessandra Tomassi, Valerio Tranchida and others. System design and code implementation Henryk Rybinski and Mariusz Suchorowski