1. Andrews M., Which acoustic speed? in: Proceedings of the 13th International symposium on nondestructive testing of wood, Forest Products Society, Madison, 2004, pp. 43-52.
2. Carter P., Lausberg M., Application of Hitman acoustic technology: The Carter Holt Harvey Experience. Tools and technologies to improve log and wood product segregation, 4th Wood quality workshop, NZ Forest Industry Engineering Association, Rotorua, 2001.