Other useful resources on web
UCLA:
iPLEX: UCLA's institute for Planets and Exoplanets
Department of Earth and Space Sciences
Division of Astronomy and Astrophysics
Caltech:
Division of Geologic and Planetary Sciences
Spacecraft missions:
Mariner 10
MESSENGER
BepiColombo
Research centers:
NASA Jet Propulsion Labs
NASA Goddard Space Flight Center
Mercury information:
National Space Science Data Center
The Nine Planets