Add my answer to Exercise 4.60.

This solution is not completely correct, I become exhausted before get it
fixed.

Included are the following 4 files:

	Exercise_4.60.pdf
	Exercise_4.60.scm
	Exercise_4.60.tm
	ch4-query.scm

Thank you!
							Lawrence X. Amlord
							  Mar 27th, 2014
							  Xi'an, China