Secondary sources are also sometimes called "indirect citations." Most citation styles suggest avoiding the use of secondary sources. If you need to use a secondary source because you are unable to find the original article/source, be sure to only cite the source that you have access to and have read.
In Text examples
In Warkinton’s study (as cited in Roberts, 2020), children’s cognitive growth and development …
Or
Roberts (2020) examined Warkinton’s study on children’s cognitive growth and development……
Reference List examples
Roberts, M. (2020). Children and cognition and the development of language. Psychological Reports, 19(7), 412-419.
Note: You only include resources you accessed/read in your References list - you read the Roberts article (which referenced the Warkington article) so the Roberts article is included in your list of References (not the Warkington article).