1-The Upanishads

 translator: Max Müller
http://www.sacred-texts.com/hin/upan/index.htm
2-The Rig Veda
Translator: Ralph T.H. Griffith
http://www.sacred-texts.com/hin/rigveda/index.htm

3-The Mahabharata

http://www.sacred-texts.com/hin/m01/index.htm

4-

The Bhagavad Gita
A modern prose translation, sanctioned by the International Gita Society
http://www.sacred-texts.com/hin/gita/agsgita.htm