1. Anon . 1996 . SAS/STAT software: changes and enhancements through release 6.11 . 1104 pp. SAS Institute Inc., Cary, ISBN 1-55544-473-3 .
2. Über die Rohdichte von Fichtenholz
3. Ericson , B. 1966 . Effect of thinning on the basic density and content of latewood and heartwood in Scots pine and Norway spruce . Dept. of For. Yield Res., Royal College of For., Stockholm, Res. Notes 10, 116 pp. (In Swedish with English summary.)