SIKANJA, Severin.
 Development of Depressed Trees of Black Pine Cultures in the Region of Sumadija. ( Serbia).
<strong>Global Journal of Science Frontier Research</strong>, [S.l.], nov. 2015.
ISSN 2249-4626.
Available at: &lt;<a href="https://journalofscience.org/index.php/GJSFR/article/view/1690" target="_new">https://journalofscience.org/index.php/GJSFR/article/view/1690</a>&gt;. Date accessed: 24 may 2022.