@article {1682, title = {Interactions of elevated CO2, NH3 and O3 on mycorrhizal infection, gas exchange and N metabolism in saplings of Scots pine.}, journal = {Plant and Soil}, volume = {176}, year = {1995}, pages = {107-116}, author = {Perez-Soba, M and Dueck, T.A. and Puppi, G. and Kuiper, P.J.C.} }