Change article for fitEllipseDirect function

modules/imgproc/include/opencv2/imgproc.hpp

@@ -4342,7 +4342,7 @@ CV_EXPORTS_W RotatedRect fitEllipseAMS( InputArray points );
 
  The function calculates the ellipse that fits a set of 2D points.
  It returns the rotated rectangle in which the ellipse is inscribed.
- The Direct least square (Direct) method by @cite Fitzgibbon1999 is used.
+ The Direct least square (Direct) method by @cite oy1998NumericallySD is used.
 
  For an ellipse, this basis set is \f$ \chi= \left(x^2, x y, y^2, x, y, 1\right) \f$,
  which is a set of six free coefficients \f$ A^T=\left\{A_{\text{xx}},A_{\text{xy}},A_{\text{yy}},A_x,A_y,A_0\right\} \f$.