1. Über die Bedingungen der Mykorrhizabildung bei Kiefer und Fichte;Björkman,1942
2. The effect of strangulation on the formation of mycorrhiza in pine;Björkman;Svensk Bot. Tidskr.,1944
3. Trials in Nyasaland of introduced pines;Clements;Australian Forestry,1938
4. The significance of the mycorrhizae of Pinus radiata;Cromer;Commonwealth For. Bur. Bull.,1935