TY  - BOOK
AU  - Burggraaf,P.D.
TI  - Some observations on the course of the vessels in the wood of Fraxinus excelsior L
PY  - 1972///
PB  - Meded.Bot.Lab.Rijksuniv.,Leiden,N°162,Acta Bot.Neerl.21(1),32-47pp.
ER  -