Wikimedia
Wikipedia: Isaac Newton
In the Spanish langauge, discover the life and works of Isaac Newton. This site highlights his work and also provides links to obtain a greater understanding of these individual works.
Houghton Mifflin Harcourt
Harcourt: Biographies: Isaac Newton
A brief biography on scientist Isaac Newton, highlighting his discoveries and the book he published in 1687, "Principia", which was on his theories of gravity and laws of motion.