[1] The doppia repository. https://bitbucket.org/rodrigob/doppia/src/.
[2] Markus Mathias, Rodrigo Benenson, Marco Pedersoli, Luc Van Gool. Face detection without bells and whistles, 2014.
[3] DPM Software. https://github.com/rbgirshick/voc-dpm/tree/master.
[4] Face Detector. http://markusmathias.bitbucket.org/2014_eccv_face_detection.
[5] Pedro F. Felzenszwalb, Object Detection with Discriminatively Trained Part Based models. IEEE Transactions on Pattern Analysis and Machine Intelligence,2009.
[6] M.J. Marin-Jimenez, A. Zisserman, V. Ferrari. 「Here's looking at you, kid.」Detecting people looking at each other in videos.British Machine Vision Conference (BMVC), 2011.
[7] LEAO Software. http://www.uco.es/~in1majim/sandbox/headmview/.
[8] VOC Software. http://cs.brown.edu/~pff/latent-release4/.
[9] P Viola. Rapid Object Detection using a Boosted Cascade of Simple Features.CVPR, 2001.
[10] Voila&Jones Face Detector in OpenCV. http://docs.opencv.org/modules/objdetect/doc/cascade_classification.html#cascade- classifier-detectmultiscale.