I read the first Stridsman book and found it horrible: pedantic and sophmoric. I agree with the more scathing reviews on Amazon.
In addition to Kaufman, Conway, LeBeau, and Katz, I might add Quantitative Trading Strategies by Lars Kestner -- he seems to be about on the same level, which is not necessarily good -- and Design, Testing, and Optimization of Trading Systems by Robert Pardo.
Most "systems" writing publicly available looks at common indicators, MA crossover, RSI, "stochastics," etc., areas that are so picked over they are unlikely to produce anything of value. I suspect that the work being done by quant groups at investment banks looks a lot different from the stuff produced by the books referenced above. For one thing it would be much more statistically based and would probably involve more sophisticated securities, such as synthetics or paired securities. Basically, you want to look for pockets of inefficiency and MA crossovers and fib numbers just don't do it. That nothwithstanding, it is still important to understand over-optimization and robustness.