Authors
Mait Lang
Tartu Observatory, University of Tartu, Tõravere, Estonia
Institute of Forestry and Rural Engineering, Estonian University of Life Sciences, Tartu, Estonia
Kersti Vennik
Military Academy, Tartu, Estonia
Andrus Põldma
Military Academy, Tartu, Estonia
Tiit Nilson
Tartu Observatory, University of Tartu, Tõravere, Estonia