On approximate methods of tangent hyperbolasKaldo, Indrek; Vaarmann, OtuMathematical modelling and analysis2002 / 2, p. 253-262 On approximate methods of tangent hyperbolasKaldo, Indrek; Vaarmann, Otu7th International Conference : Mathematical Modelling and Analysis, May 31 - June 2, 2002, Kääriku, Estonia : abstracts2002 / p. 25