\pagestyle{myheadings} >\headsep=.5cm >\textwidth=11.5cm >\textheight=19.5cm >\oddsidemargin=20mm >\evensidemargin=20mm >\topmargin=-7mm \topmargin=0mm >\vspace{-15mm} \renewcommand{\thefootnote}{\arabic{footnote}} >\setcounter{footnote}{0} > \english >\bibitem{rudin}{\sc Walter Rudin },{\it Principles of Mathematical Analysis}, McGraw-Hill, > 1976. >\bibitem{kolm} {\sc A. N. Kolmogorov, S. V. Fomin }, {\it Introductort Real Analysis}, > New York, 1969.