Published Drops for crops: modelling crop water productivity on a global scale by Liu J., Zehnder A.J.B., Yang H. 295_300_486_LIU_10-3.pdf
Published Malaria situation in Bulgaria and surveillance measures (1991-2000) by Kurdova R.I., Vutchev D.I. and Petrov P.P. Kurdova_153_162.pdf