Bibliography

Banks, J. Houston, Algebra: Its Elements and Structure,
McGraw-Hill, St. Louis, (1965), 116.

Dodge, Clayton W., Numbers and Mathematics, Prindle, Weber,
and Schmidt, Boston, (1969), 139-185.

Enns, Don K., "0/0 is a 'no-no'", Journal of the Kansas
Association of Teachers of Mathematics, 21.

Suppes, Patrick, Introduction to Logic, D. Van Nostrand Co.,
Princeton, NJ, (1957), 163-9.

Plus many ideas, encouragement, and discouragement from friends,
teachers, students, in conversations both written and oral.