Klavina,D., Muiznieks,I., Gaitnieks,T., Lazdins,A., Nikolajeva,V., Bardule,A. and Menkis,A., Fine root development and mycorrhization in Norway spruce stands a year after fertilization with potassium sulphate and wood ash. Journal of Forest Science 62:17-23. https://www.ncbi.nlm.nih.gov/nuccore/KT692925