"indicated that several" is correct and can be used in written English.
For example, "The teacher indicated that several students had not yet finished their assignments."
The findings indicated that several work climate factors could function as leading indicators, implying that the work climate approach has been underestimated in safety research.
Intensive research between World Wars I and II indicated that several synthetic compounds were more effective.
And so the pile of abandoned passports indicated that several workers had fled, leaving their documents behind.
The online literature indicated that several scanners use CCD image sensors, and further reading sparked an interest in CCD sensors.
The research also indicated that several sessions of counseling were more effective than only one.
The preliminary biological evaluation indicated that several compounds exhibited comparable potency with Sorafenib.
The in vitro binding assay indicated that several compounds are potent selective V2 receptor antagonists.
The results indicated that several reaction steps occurred in the solution.
The results indicated that several personality disorders were systematically associated with these aspects of emotional intelligence.
The documents, which include billing and medical records, indicated that several players received performance-enhancing drugs from a clinic director.
