%0 Journal Article %A H. Bickel, S. %T The Maximum Depth Principle as a Dual to Fermat's Minimum Time Principle %D 1998 %J , %V %@ 2214-4609 %C cp-110-00175 %R https://doi.org/10.3997/2214-4609.201408274 %I European Association of Geoscientists & Engineers, %X %U https://www.earthdoc.org/content/papers/10.3997/2214-4609.201408274