Clasificación de la Biblioteca del CongresoQE399.2

21st century(11) American(29) analysis(6) antique(47) archaeology(14) art(46) bibliography(8) biology(8) California(15) Canada(17) caves(7) chemistry(61) children(16) children's(24) classic(12) diamond(8) dictionary(17) earth(42) ecology(9) education(8) educational(8) environment(11) family(8) general science(5) geography(30) geology(1,722) gold(6) Great Britain(6) guide(104) guidebook(99) handbook(10) healing(9) hiking(6) historical(16) history(68) horror(6) informational(8) insects(6) instructional(6) juvenile(13) juvenile non-fiction(5) kids(7) local(5) magic(5) maps(29) Mexico(6) Michigan(10) mining(43) natural science(25) natural world(10) nature(319) New Jersey(7) New Mexico(18) North America(16) outdoors(5) photographs(48) photography(9) picture book(14) reference(487) references(16) regional(88) rock(48) school(8) science(900) science and technology(6) science nonfiction(5) Southwest(7) spirituality(8) stone(13) stones(68) systems(5) travel(57) us(10) usa(39) volcanoes(8) Washington(11) youth(5)