Hello kih
I stopped manage this portfolios. I will eventually trade gold and silver etfs in U.S. Portfolio thread.
See here:
http://www.trade2win.com/boards/stocks/167512-u-s-portfolio-11.html#post2133736
About your question, I don't know any ETF book, and I assume that you don't need to read books about this.
First of all, you need to learn how to analyze the market, and only then you need to search ETFs or stocks.
For search ETFs you need to decide first if you want to go long or short and choose the amount of leverage that is appropriate from 1x to 3x.
(no leveraged) 1x (100% of the benchmark's daily performance)
2x (200% of the benchmark's daily performance)
3x (300% of the benchmark's daily performance)
If you want go short, you can buy inverse ETFs.
You can use this site to search ETFs
The Web's Best ETF Screener | ETF Database
The Web's Best ETF Screener | ETF Database