Tatra Tatra Mountains Mathematical Publications : Number theory, algebra and cryptology '18. -- Vol. 73 (2019). -- Bratislava : Slovak Academy of Sciences, 2019. -- 193 s. -- ISSN : 1210-3195. Grošek, Otokar, 1950-. Nemoga, Karol, 1953-. Paštéka, Milan. Zajac, Pavol, 1980- In: Tatra Mountains Mathematical Publications. -- ISSN 1210-3195. -- Slovak Academy of Sciences.