added bib link to the article in GPU docs (for HOG)

doc/gpu_object_detection.tex

 \section{Object Detection}
 
 \cvclass{gpu::HOGDescriptor}
-\href{http://www.acemedia.org/aceMedia/files/document/wp7/2005/cvpr05-inria.pdf}{Histogram of Oriented Gradients} descriptor and detector.
+Histogram of Oriented Gradients \cite{dalal_hog} descriptor and detector.
 
 \begin{lstlisting}
 struct CV_EXPORTS HOGDescriptor

doc/opencv.bib

@@ -272,6 +272,13 @@
     month = {October}
 }
 
+@article{dalal_hog,
+    author = {Navneet Dalal and Bill Triggs},
+    title = {Histogram of Oriented Gradients for Human Detection},
+    booktitle = {CVPR},
+    year = {2005}
+}
+
 # '''[Bradski98]''' G.R. Bradski. Computer vision face tracking as a component of a perceptual user interface. In Workshop on Applications of Computer Vision, pages 214?219, Princeton, NJ, Oct. 1998.<<BR>> Updated version can be found at http://www.intel.com/technology/itj/q21998/articles/art\_2.htm.<<BR>> Also, it is included into OpenCV distribution ([[attachment:camshift.pdf]])
 # '''[Burt81]''' P. J. Burt, T. H. Hong, A. Rosenfeld. Segmentation and Estimation of Image Region Properties Through Cooperative Hierarchical Computation. IEEE Tran. On SMC, Vol. 11, N.12, 1981, pp. 802-809.
 # '''[Canny86]''' J. Canny. A Computational Approach to Edge Detection, IEEE Trans. on Pattern Analysis and Machine Intelligence, 8(6), pp. 679-698 (1986).