This package is not distributed on CRAN. The easiest/quickest way to get IPSUR (which at the moment doesn't do what it is supposed to do) is to install the devtools package if you don't have it ...

Based on the Central Lecture Course by Dr. Frederic P. Schuller (A thorough introduction to the theory of general relativity) introducing the mathematical and physical foundations of the theory in 24 ...

Ask the publishers to restore access to 500,000+ books. An icon used to represent a menu that can be toggled by interacting with this icon. A line drawing of the Internet Archive headquarters building ...