TY  - BOOK
AU  - Verdoorn,Frans
AU  - Alston,A.H.G.
TI  - Manual of pteridology,
AV  - QK523 .V47
PY  - 1938///
CY  - The Hague
PB  - M. Nijhoff
KW  - Ferns
N1  - Some of the articles are in German; Contains bibliographies
ER  -