{"first_sentence": {"type": "/type/text", "value": "The purpose of a Heating, Ventilating, and Air Conditioning (HVAC) system is to provide and maintain a comfortable environment within a building for the occupants or a suitable environment for the process being conducted."}, "physical_format": "Hardcover", "subtitle": "Operation and Maintenance (3rd Edition)", "last_modified": {"type": "/type/datetime", "value": "2008-04-30 09:38:13.731961"}, "weight": "2.3 pounds", "languages": [{"key": "/l/eng"}], "publishers": ["Prentice Hall"], "number_of_pages": 300, "isbn_13": ["9780130610393"], "id": 12540236, "edition_name": "3rd edition", "isbn_10": ["0130610399"], "publish_date": "November 12, 2001", "key": "/b/OL9287269M", "authors": [{"key": "/a/OL533425A"}], "title": "HVAC Controls", "type": {"key": "/type/edition"}, "subjects": ["Heating, lighting, ventilation", "Heating And Ventilation Engineering", "Technology", "Technology & Industrial Arts", "Science/Mathematics", "Engineering - Mechanical", "Power Resources"], "physical_dimensions": "9.3 x 6.3 x 0.9 inches", "revision": 1}