Pyka. (2013). Long Term Economic Development (1.). Springer Berlin Heidelberg.
Cita Chicago (17th ed.)Pyka. Long Term Economic Development. 1. Springer Berlin Heidelberg, 2013.
Cita MLA (8th ed.)Pyka. Long Term Economic Development. 1. Springer Berlin Heidelberg, 2013.
Atenció: Aquestes cites poden no estar 100% correctes.