artículo científico publicado en 1985

abstract published in 2000

field study published in 1978

field study published in 1986

field study published in 1982

field study published in 1984

field study published in 1986

field study published in 1986

field study published in 1987

field study published in 1990

field study published in 1994

field study published in 1991

artículo científico publicado en 1982

artículo científico publicado en 1996

chapter published in 1986

field study published in 1976

field study published in 1977