1. Anon. 1994. Skogsvårdslagen. Handbook. National Board of Forestry, Jönköping, Sweden, 66 pp. ISBN 91-88462-11-0. (In Swedish.)
2. Anon. 1999. SYSTAT 9. Statistics I. SPSS, Chicago, IL. ISBN 1-13-026157-2.
3. Anon. 2000. Statistical Yearbook of Forestry 2000. National Board of Forestry, Jönköping, Sweden. ISBN 91-88462-47-1. (In Swedish with English summary.)
4. Effects of spacing and cutting cycle on the yield of poplar grown as an energy crop