Pre-Calculus in 2001

Precalculus: A Self-Teaching Guide by Slavin, Steve, Crisonino, Ginny

Precalculus: A Self-Teaching Guide by Crisonino, Ginny, Slavin, Steve

Codes and Ciphers: Julius Caesar, the Enigma, and the Internet by Churchhouse, R. F., Churchhouse, Robert, R. F., Churchhouse

Codes and Ciphers: Julius Caesar, the Enigma, and the Internet by Churchhouse, R. F., Churchhouse, Robert, R. F., Churchhouse