Here are various documents from Solid State Products, Inc. (SSPI), including data and application notes.

SSPI 1959 Circuit Applications of the Silicon Controlled Switch and SCR D420-02 - The "Controlled Switch" (CS) made by SSPI is essentially a sensitive-gate Silicon-Controlled Rectifier (SCR). Thus, this document provides a myriad of circuits using modern sensitive gate SCRs. Lots of circuits.