Skelly, J.M., Innes, J.L., Savage, J.E., Snyder, K.R., Vanderheyden, D., Zhang, J., Sanz, M.J. 1999. Observation and confirmation of foliar ozone symptoms of native plant species of Switzerland and southern Spain. WATER AIR SOIL POLL, 116:227-234.
Skelly, J.M., Innes, J.L., Savage, J.E., Snyder, K.R., Vanderheyden, D., Zhang, J., Sanz, M.J. 1999. Observation and confirmation of foliar ozone symptoms of native plant species of Switzerland and southern Spain. WATER AIR SOIL POLL, 116:227-234.