First found it in the 4-Hour Work week.  

I imagine this will take at least half of my work week (You can tell me if I'm right or not) .

The 4 Hour Work Week and Millionaire Real Estate Investor are on their way from AmazonI'm reading Think and Grow Rich right now.

I have also been listening to the podcasts and a lot of guests have recommended E-Myth.I really enjoyed the 4-Hour Work Week and The Art of The Deal, because they makes you think about the possibilities and the WHY when you are investing to earn a secondary source of income!

The 4-hour work week by Tim Ferris has some great info. 

Bertand Russell correctly predicted that as we become more technologically savvy, there will be less demand for a typical work week, much less the worker himself/herself. 

We as a nation need to normalize the expectation that 40 hours is not a work week but that working 12 hours a day is working a "half day".  

My goal as an investor is continue a focus on acquiring a mixture of SF and MF properties with an emphasis on cash flow, with enough units in 5 years to take my first "mini retirement"(Yes, I am huge "4 Hour Work Week" fan) and travel the world freely.

Do yourself a favor and read the 4 hour workweek.  

In his book "The Four Hour Work Week", Tim Ferriss recommends that idea.