W. Gordon Simpson
F. N. Howes
Robert L. Davidson
Joseph W Prane
Michael Ash
Edward Richards Bolton
John Philip Mason
Rosemary Gianno
Joseph Lauterer
Everett William Boughton
United States. Environmental Protection Agency. Office of Air Quality Planning and Standards
Ernest John Parry
Ralph Lawrence Guile
Parker Cairns McIlhiney
Canada. Agriculture, Department of. Botany and Plant Pathology Division
Enviro Control, inc
Canada. Botany and Plant Pathology Division.
Unknown Author