Hits 1-2 within 2 documents
Hits 1-2 within 2 documents
Author(s): Bala, Christian; Kleinschmidt, Christian; Rick, Kevin; Schuldzinski, Wolfgang.- 2017. 7-15p.
Author(s): Korotayev, Andrey; Grinin, Leonid
Source: Uchitel Publishing House, 2019