1. Location humidity and the sugar content in the plants;ILJIN;Planta,1929
2. New findings concerning the origin and combating of mass propagation of phytophagous insects of pines and spruces;SCHWENKE;Zt. ang. Ent.,1962
3. Differences in the sugar content of leaves and pine-needles and their relations to the volume change of phytophagous insect species;SCHWENKE;Commun. Forestry Administration of Bavaria,1964