Here is an example of books with Library of Congress Classification System call numbers. They are in order as they would be found on the shelf.

HM before HN			90 before 373
HM 13 .C49 1986	HN 18 .K3 1953	HN 90 .T5 1993	HN 90 .U5 1996	HN 373 .D5 1973	HQ 9 .E52 1995	HQ 9 .E52 2003
		.T before .U			1995 before 2003