A regression analysis procedure is developed for use when the dependent variable is a point on the circumference of a circle, surface of a sphere, etc. The computations required for estimating and testing certain hypotheses regarding the parameters of linear-type models are described in detail. The method is illustrated with an application to the analysis of vector-cardiogram projections
A Regression Technique for Angular Variates
Gould, AL. (1969). A Regression Technique for Angular Variates. Biometrics, 25(4), 683-700.