1. Browning , B. L. 1963. The Chemistry of Wood, 88New York: Interscience.
2. Pearl , A. I. 1967. The Chemistry of Lignin, 276New York: Marcel-Dekker.
3. Sarkanen , K. V. and
Ludwig , C. H. 1971. Lignins, 575New York: Wiley-Interscience.
4. Supercritical-Gas Extraction of Spruce Wood