Question: Jim Keller is a microprocessor engineer most well known for his work at AMD and Apple, he was involved in designing which 32-bit package on package (PoP) system-on-a-chip (SoC) designed by Apple Inc. and manufactured by Samsung? 
Sentence (from "Apple A4"): The Apple A4 is a 32-bit package on package (PoP) system-on-a-chip (SoC) designed by Apple Inc. and manufactured by Samsung.
Relevant evidence: Yes