16GB 2X 8GB Memory for HP EliteBook 8440w 8540w Mobile Workstation Quad Core DDR3 PC3-10600 1333MHz 204 pin SODIMM RAM (PARTS-QUICK BRAND) at Amazon.com
Nokotion Kaq00 La-4951p 595764-001 Laptop Motherboard For Hp Elitebook 8540p 8540w Ddr3 With Graphics Slot Not Support I7 - Laptop Motherboard - AliExpress
Extra RAM not working in HP elitebook 8540w - Microsoft Community
Review HP EliteBook 8540p Notebook - NotebookCheck.net Reviews
A-Tech 8GB Module for HP EliteBook 8540w Mobile Workstation (Quad Core Processors) Laptop & Notebook Compatible DDR3/DDR3L PC3-12800 1600Mhz Memory Ram (ATMS266664B12351X1) at Amazon.com
Protech Review: HP EliteBook 8540w Mobile Workstation Review
Solved: Missing RAM slot in EliteBook 8540p - HP Support Community - 1800127