scientific article

scholarly article in Sida, vol. 9 no. 2, 1981

scientific article published in 1990

scientific article published in 1985

scientific article

Urbana: University of Illinois Press, c1997.

scientific article (publication date: August 1983)

scientific article published in 1986

scientific article (publication date: February 1985)

scientific article published on 09 May 2006

scientific article (publication date: November 1978)

scientific article published in 1983

scientific article published in 1991

scientific article published on February 1987

scientific article (publication date: February 1986)

scientific article published on February 1987

scientific article (publication date: February 1988)

scientific article published in 1977

scientific article

scientific article (publication date: November 1977)

scientific article published in January 1983

scientific article published in 1984

scientific article published in 1978

scientific article published in 1978

scientific article published in 1984

scientific article published in 1981

scientific article (publication date: May 1975)

scientific article

[Urbana], University of Illinois at Urbana-Champaign, College of Agriculture, [1974]

scientific article (publication date: November 1982)