Update my answer to Exercise 2.88.

Modified are the following 2 files:

	Exercise_2.88.pdf
	Exercise_2.88.tm

Newly added are the following 2 files:

	Exercise_2.88.scm
	Test_of_Exercise_2.88.scm

Thank you!
							Lawrence R. Amlord
							   Aug 19th, 2013
							   Fuzhou, China