Issue: There are several approaches for approximating the unknown expansion factors for k-tree sampling that are currently not included in the estiamtion routines.
Solution: Add the approximations of Kleinn and Vilcko (2006) and Prodan's method. Another possibility would be to add the design-unbiased approach from Kleinn and Vilcko (2006) - Voronoi polygons; maybe in the long run.
Issue: There are several approaches for approximating the unknown expansion factors for k-tree sampling that are currently not included in the estiamtion routines.
Solution: Add the approximations of Kleinn and Vilcko (2006) and Prodan's method. Another possibility would be to add the design-unbiased approach from Kleinn and Vilcko (2006) - Voronoi polygons; maybe in the long run.