Correction to: Uncertainty Assessment over any Volume without Simulation: Revisiting Multi-Gaussian Kriging (Mathematical Geosciences, (2021), 53, 6, (1375-1405), 10.1007/s11004-020-09907-9)

The publisher apologized for this unfortunate error, which has been corrected in the original article. Due to a processing error, all upper sigma symbols, denoting covariance matrices, appeared without bold. All upper sigma Greek letters throughout the paper should be in bold. For example, in page 4.