Differences Between VMware vSphere, vCenter, ESXi Free vs ESXi Paid, Workstation Player & Pro
VMware vSphere: Products, Price and Features | Blog by Raihan Al-Beruni
A quick look at VMware vSphere Editions and Licensing
How to release a VMware unused license from a host? New licensing scheme? - Server Fault
VMware vSphere Essentials Kit
VMware vSphere Essentials Kit ( v. 6 ) - subscription license ( 1 year ) This is Essential Support to be Purchased with tem #: 32-331-029|Mfr. Part #: VS6-ESSL-KIT-C - Newegg.com
VMware vSphere 6 Essentials Plus Kit for 3 hosts VS6-ESP-KIT-C
VMware vCenter Server Licensing Models
VCS7-FND-C | VMware vSphere Software | Aventis Systems