SQL Tuning
Dan Tow
ZoomNotes for Linear Algebra
Gilbert Strang
An Introduction to R for Spatial Analysis and Mapping
Brunsdon, Chris & Comber, Lex
Mathematica Tutorial: Dynamic Interactivity
Theodore Gray & Lou D'Andria
Linux on the Mainframe
John Eilert & Maria Eisenhaendler & Dorothea Matthaeus & Ingolf Salm