DUFEK, Jaroslav. Age structure and the burden carried by the productive population of the Czech Republic. In Agricultural economics : an international journal = mezinárodní vědecký časopis. - Prague : Institute of Agricultural and Food Information, 2006. ISSN 0139-570X, 2006, vol. 52, no. 2, s. 67-75. Dostupné na : <http://www.agriculturejournals.cz/publicFiles/57995.pdf>