1. Arcara PG, Piovanelli C, Nannipieri P (1974) Variazioni della microflora del suolo indotte dallo impiego del pirofosfato per l'estrazione degli enzimi. Ann 1st Sper Dif Suolo 5:319?322
2. Barriuso E (1985) Caracterisation des fractions organo-minerales et des constituants humiques d'un sol de pelouse subalpine. PhD thesis, University of Nancy
3. Barriuso E, Adreux F, Portal JM (1985) Quantification des acides humiques et fulviques d'un sol acide de montagne. Discussion methodologique. Sci Sol 1:23?25
4. Batistic L, Sarkar JM, Mayaudon J (1980) Extraction, purification and properties of soil hydrolases. Soil Biocheiochem 12:59?63
5. Bremner JM, Lees M (1949) Studies on soil organic matter. II. The extraction of organic matter from soil by neutral reagents. J Agric Sci 39:275?279