GOGOLA, Ján. On I-convergence and Niven's function. In Aplimat 2008 : 7th international conference, February 5 - 8, 2008 Bratislava. - Bratislava : Faculty of Mechanical Engineering, Slovak University of Technology in Bratislava, 2008. ISBN 978-80-89313-02-0, s. 95-99.