Component Software: Beyond Object-Oriented Programming, 2/E (Addison-wesley Component Software)
Then you should also watch the talks he did later at Unite, after joining Unity.
As I mentioned regarding ECS, on CS literature.
"Component Software: Beyond Object-Oriented Programming"
First edition (1997) used Component Pascal, C++ and Java, while the 2nd edition replaced Component Pascal with C#.
"Component-Based Software Engineering: Putting the Pieces Together"
ECS and Data-oriented programming aren't the same thing.