Secondary source in a book
Referencing a secondary source from a book
Use secondary sources only when you cannot obtain the primary source of information.
Page numbers must be included.
Gardener (as cited in Biggs & Tang, 2007) states that if as a teacher you cover a wide range of topics "you are guaranteeing that most kids will not understand, because they haven't had time enough to go into things in depth" (p. 82).
Page numbers may be required.
There is a delicate balance in teaching between depth of learning and breadth of learning, which means the greater the coverage of a topic the lesser the depth of understanding that may be achieved by students (Gardiner as cited in Biggs & Tang, 2007).
Biggs, J., & Tang, C. (2007). Teaching for quality learning at university: What the student does (3rd ed.). Berkshire, England: Open University Press.