Evaluate the collective function of references cited together in a given text segment.
Classify their combined role into one of the following categories: 'method', 'background', or 'result'.

Text:Sequence Frames Initial position Challenges Biker [10, 35] 1-180 250 110 45 75 Abrupt motion Bird [9] 1-408 443 94 37 27 Abrupt motion, disappear, and reappear Bolt [9, 10, 35] 1-350 336 165 25 60 Fast movement Cartoon 1-200 83 134 56 56 Significant pose variation Coke [8] 1-292 148 82 20 35 Drastic illumination variation and occlusion Dragon baby [35] 1-112 167 74 40 70 Abrupt motion, pose variation Girl move [5, 9] 1-1500 303 161 28 113 Significant occlusion Indian dancer 1-150 157 61 20 23 Pose variation and abrupt motion Lemming [9] 1-681 40 200 54 92 Abrupt motion and significant occlusion Liquor [9] 1-1553 257 226 67 125 Occlusion and fast movement Panda [10, 37] 1-241 257 171 45 55 Fast movement, occlusion, and pose variation Stennis [5] 1-55 133 39 23 23 Abrupt motion and fast movement Surfer [35] 1-400 282 165 35 45 Significant and long duration occlusion Sylvester [2, 10] 1-1344 125 56 43 50 Drastic illumination and pose variations Woman [38, 41] 1-553 208 125 27 75 Occlusion and significant appearance changes
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