Polya, G.
How to solve it : a new aspect of mathematical method - 2d ed. - New Jersey Princeton U.P. 1945 - 253 p.
reprinted on 1971
51.001 / P6
How to solve it : a new aspect of mathematical method - 2d ed. - New Jersey Princeton U.P. 1945 - 253 p.
reprinted on 1971
51.001 / P6