Each of three view-points, that of statistics, economic theory, and mathematics, is necessary, but not by itself a sufficient, condition for a real understanding of the quantitative relations in modern economic life. It is the unification of all three that is powerful. And it is this unification  that constitutes econometrics.
RAGNAR FRISCH
Robert Kelm
Kurs złoty/euro: teoria i empiria
Wydawnictwo Uniwersytetu Łódzkiego, Łódź, 2013, 978-83-7525-821-9
Władysław Welfe
Macroeconometric Models
Springer, ., 2013, .
Piotr Karp, Piotr Kębłowski, Michał Majsterek, Aleksander Welfe
Analiza kointegracyjna w makromodelowaniu
PWE, Warszawa, 2013, 978-83-208-2039-3
Aleksander Welfe (ed.)
New Directions in Macromodelling
ELSEVIER, Amsterdam, 2004, 0-444-51633-6
Władysław Welfe
Long-term macroeconomic models. The case of Poland
Economic Modelling, Vol. 28, 2011, pp. 741-753
Anna Staszewska-Bystrova, Peter Winker
Constructing narrowest pathwise bootstrap prediction bands using threshold accepting
International Journal of Forecasting, Vol. 29, 2013, pp. 221-233
Piotr Kębłowski, Aleksander Welfe
A risk-driven approach to exchange-rate modelling
Economic Modelling, Vol. 29, 2012, pp. 1473-1482
Wojciech Grabowski, Aleksander Welfe
Global stability of dynamic models
Economic Modelling, Vol. 28, 2010, pp.782-784
Anna Staszewska-Bystrova
Bootstrap prediction bands for forecast paths from vector autoregressive models
Journal of Forecasting, Vol. 30, No. 8, pp. 679-752
Michał Majsterek, Aleksander Welfe
Price-wage nexus and the role of a tax system
Economic Change and Restructuring, Vol. 45, No. 1-2 , 2012, pp.121-133
Piotr Kębłowski, Aleksander Welfe
Estimation of the equilibrium exchange rate: The CHEER approach
Journal of International Money and Finance, Vol. 29, 2010, pp. 1385-1397