1 Subjects: “...energy efficiency...”

2 Subjects: “...efficiency...”

3 Subjects: “...efficiency...”

4 Subjects: “...efficiency engines...”

5 Subjects: “...efficiency ranking...”

6 Subjects: “...exergy efficiency...”

7 Subjects: “...tractive efficiency...”

8 Subjects: “...nitrogen use efficiency...”

9 Subjects: “...cost efficiency...”

10 Subjects: “...phosphorus use efficiency...”

11 Subjects: “...efficiency...”

12 Subjects: “...efficiency...”