Reference

Marja Liisa Sutinen, T. Holappa, K. Kujala (1999): Seasonal Changes in Soil Temperature and in the Frost Herdiness of Scots pine Roots under Subarctic Conditions: Comparison with Soil Temperature and Snow-Cover under Different Simulated Winter Conditions. – Phyton, Annales Rei Botanicae, Horn – 39_4: 213 - 218.