Most often, an author wants to use the ideas of another author to support or advance their own ideas. Reference to the work of others can also be used to establish what is already known as a foundation to the author’s research. In these cases, a reference to the other work may be adequate, such as:
Similar observations have been made by others (Stalkup 1990; Haajizadeh et al. 199; Jessen et al. 2004; Moulds et al. 2005). Dispersion is also an important effect in water injection where miner scales are formed by the mixing of injected and reservoir brines (Sorbie and MacKay 2000; Delshad and Pope 2003), in the underground storage of gases where mixing of the injected and in-situ gas changes the quality of the stored gas (Verlaan et al 1998), and in proposed methods of enhanced natural-gas recovery by injecting anthropogenic CO2 (Oldenburg et al. 2001).
[Quotation taken from John A.K., Lake, L.W. Bryant, S.L., AND Jennings, J.W. 2010. Investigation of Mixing in Field-Scale Miscible Displacements Using Particle-Tracking Simulations of Tracer Floods with Flow Reversal. SPE J 15 (3) 598. SPE-113429-PA.doi:10.2118/113429-PA.]
If it is necessary to include some of the specific findings from other work, then paraphrasing is likely to work best. Reference to the original sources is still required. Paraphrasing does not mean changing one or two words – it means rewriting the ideas in your own words in a way that will further support your work. For example:
Given sufficient residence time and the correct physical conditions, crude-oil emulsions can become partially or fully resolved. Therefore, separator vessels need to be sized appropriately to get the best residence time for the fluids being processed. Sometimes, retrofitting of vessels can occur to make, for example, two-phase separators into three-phase separators to improve residence time (Kokal and Al-Ghamdi 2008).
[Quote take Wylde J.J. Coscio, S., and Barbu, V. 2010 A Case History of Heavy-Oil Separation in Northern Alberta: A Singular Challenge of Demulsifier Optimization and Application. SPE Prod & Oper 25 (1): 20. SPE-117177-PA. doi: 10.2118/117177-PA.]
The above quote is paraphrasing ideas from several places in the referenced paper, but most specifically, the passage below:
Process variables include oil and water-flow rates, temperatures, water cuts, and GOSP operating conditions. A higer residence time of fluids in the GOSP will generally lead to better separation and better performance, all other variables being constant. Besides the redience time, process retrofits in the vessels also tend to enhance performance.
Quote taken from Kokal, S. and AL-Ghamdi, A. 2008. Performance Appraisals of Gas Oil Separation Plants. SPE Prod and Oper 23 (2): 287. SPE-10854-PA. doi 10.2118/102854-PA.]