  In this work, we show a phenomenological alloy-like fit of the thermal
conductivity of (A)d1:(B)d2 superlattices with d1 /= d2, i.e. non-symmetric
structure. The presented method is a generalization of the Norbury rule of the
summation of thermal resistivities in alloy compounds. Namely, we show that
this approach can be also extended to describe the thermal properties of
crystalline and ordered-system composed by two or more elements, and, has a
potentially much wider application range. Using this approximation we estimate
that the interface thermal resistance depends on the period and the ratio of
materials that form the superlattice structure
