annual variation of water level
anomalous variation of water temperature
coefficient of variation of grade
equation of variation of energy
forecast of the variation of water level
Hamilton’s law of variation principle
Law of water-moving and variation
method of variation of constant
method of variation of parameters
seasonal variation of water type distribution
the equation of variation of energy
time-variation law of arc length
variation law of antibody titers
variation law of soil water content
variation of water and sand
variation of water depth
variation of water level
variation of water permeability