Bài báo khoa học

1916, Piper Charles V.

1951, Burton, Glennw

1985, Bryan, Frank L

1994, Andersen, Per Pinstrup

1994, Eele, Graham

1996, Sjiiberg, A.-M

1996, Maxwell, Daniel G.

1997, Reitan, Kjell Inge, Rainuzzo, Jose R., 0ie, Gunvor, Olsen, Yngvar

1917, Fippin Elmer O.

1983, Rambo. A. Terry.

1991, Johnston, Lee J., Hawton, Jerry D.

1994, Courtois, F

1994, Campbell Platt, Geoffrey

1996, Tschirley, David, Donovan, Cynthia, Weber, Michael T.

1996, Teklu, T

1997, Karlen, D. L., Mausbach, M.J., Doran, J.W., Cline, R.G., Harris, R.F., Schuman, G.E.

1918, Skinner J. J.

1984, Garzon, Jose M

1994, Kennedy, Eileen

1994, Quinn, Victoria J

1995, Pimentel, David, Harvey, C., Resosudarmo, P.

1996, Maxwell, Simon

1996, Silva, Joao Gomes da

1998, Uphoff, Norman