@article {Effect1969,
title = {Effect of Grouping on the Efficiency of Least Squares Regression - Study of a Simple Case},
year = {1969},
url = {https://www.esri.ie/publications/effect-of-grouping-on-the-efficiency-of-least-squares-regression-study-of-a-simple-case},
author = {Geary, Roy C},
journal = {Memorandum Series 59},
}