1. Makkonen, H., Sarkanen, K., Johanson, L., Gratzl, J. and Ernst, C. 1971. Paper presented at the 25th TAPPI Alkaline Pulping Conference. Houston. October25–281971.
2. Pekkala, O. 1980. Paper presented at the EUCEPA Syaposlua. June2–51980, Helsinki.
3. Brink, D. and Lin, S. 1978. Paper presented at the 1978 TAPPI Pulping Conference. October26–291978, Atlanta.
4. Pretreatment of Scots Pine with Nitric Oxide and Oxygen before Kraft Cooking