14. Segments The following table presents the Companys operations by reportable segment. The Company is managed through three reportable segments, Technology &amp; Analytics Solutions, Research &amp; Development Solutions and Contract Sales &amp; Medical Solutions . Technology &amp; Analytics Solutions provides mission-critical information, technology solutions and real-world insights and services to the Companys life sciences customers. Research &amp; Development Solutions, which primarily serves biopharmaceutical customers, provides outsourced clinical research and clinical trial related services. Contract Sales &amp; Medical Solutions provides health care provider (including contract sales) and patient engagement services to both biopharmaceutical customers and the broader healthcare market. Certain costs are not allocated to the Companys segments and are reported as general corporate and unallocated expenses. These costs primarily consist of stock-based compensation and expenses related to integration activities and acquisitions. The Company also does not allocate depreciation and amortization or impairment charges to its segments. Prior period segment results have been recast to conform to changes to management reporting in 2019. The recast impacts the allocation of selling, general and administrative expenses for 2018. Asset information by segment is not presented, as this measure is not used by the chief operating decision maker to assess the Companys performance. The Companys reportable segment information is presented below: Three Months Ended March 31, (in millions) 2019 2018 Revenues Technology &amp; Analytics Solutions $ 1,075 $ 985 Research &amp; Development Solutions 1,416 1,365 Contract Sales &amp; Medical Solutions 193 213 Total revenues 2,684 2,563 Costs of revenue, exclusive of depreciation and amortization Technology &amp; Analytics Solutions 633 547 Research &amp; Development Solutions 946 923 Contract Sales &amp; Medical Solutions 169 182 Total costs of revenue 1,748 1,652 Selling, general and administrative expenses Technology &amp; Analytics Solutions 184 182 Research &amp; Development Solutions 181 174 Contract Sales &amp; Medical Solutions 15 18 General corporate and unallocated 39 46 Total selling, general and administrative expenses 419 420 Segment profit Technology &amp; Analytics Solutions 258 256 Research &amp; Development Solutions 289 268 Contract Sales &amp; Medical Solutions 9 13 Total segment profit 556 537 General corporate and unallocated (39 ) (46 ) Depreciation and amortization (295 ) (282 ) Restructuring costs (12 ) (26 ) Total income from operations $ 210 $ 183