This information appears on page 15 of the source. Which citation format is correct?

(Price et al. 15)

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The estimated ARMS effect indicates a 17-percent increase in yields for herbicide-tolerant cotton adopters nationwide. In some regions, herbicide-tolerant cotton yields may have been lower than for conventional varieties. In particular, farmers in the Mississippi Portal encountered serious and unexpected problems with their herbicide-tolerant cotton during the 1997 growing season (Virginia Cooperative Extension). Some growers found deformed bolls and bolls that dropped off the plants. About 20 percent of the region’s herbicide-tolerant cotton was affected. However, the problems may have been caused by factors other than the herbicide-tolerant technology itself, such as soil type and weather conditions.

—Gregory Price, William Lin, José Falck-Zepeda, and Jorge Fernandez-Cornejo.