Reference

Michael Tausz, Andrzey Bytnerowicz, Wilfried Weidner, M. J. Arbaugh, P. Padgett, Dieter Grill (1999): Pigments and Photoprotection in Needles of Pinus ponderosa Trees without Symptoms of Ozone Injury. – Phyton, Annales Rei Botanicae, Horn – 39_4: 219 - 224.