http://digfir-published.macmillanusa.com/video_human_comm_accessible/video_human_comm_accessible_ch75.html
Chapter
75. Definition: Operational (functional)
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http://digfir-published.macmillanusa.com/video_human_comm_accessible/video_human_comm_accessible_ch75_dlap.xmlDLAP questions59d61e4e7894d28c67000000