“…activity to fall to 50 and 10% of the initial value (Bryan, Bentivolgio andBeerel 1964, De Roo, Goris, Van der Schvern, Cosemans, Billiet andGyselen 1969), slopes of washout curves for different regions (Kaihara, Natarajan, Maynard and J5'agner 1969, MacIntyre and Inkley 1969, Burdine, Murphy, Alagarsami, Ryder and Carr 1972 and height over area washout curve (Secker-Walker, Hill, Markham, Baker, Wilhelm, Anderson and Potchem 1973).…”