1907 – .
Bibliografía (22 obras)
The illustrated book of wildflowers and shrubs
1993
The illustrated book of trees
1983
Indian harvests
1973
The wondrous world of seedless plants
Home guide to trees, shrubs, and wild flowers
1970
Recognizing flowering wild plants
1968
How to recognize flowering wild plants
Familiar trees of America
1967
Familiar trees ofAmerica
Recognizing native shrubs
1966
How to recognize shrubs
How to recognize trees
1962
The study of flowers made simple
The book of trees
1957
The book of shrubs
Mammal survey of northeastern Pennsylvania
1952
The shrubs of Pennsylvania
Birds of the Pymatuning region
The trees of Pennsylvania
1950
Mammal survey of southwestern Pennsylvania
