# Farkas, Learn Dewey Decimal Classification, 2015 > [!cite] > Farkas, Lynn. *Learn Dewey Decimal Classification: International Edition*. 23rd edition. TotalRecall Publications, 2015. [https://archive.org/details/learndeweydecima0000fark](https://archive.org/details/learndeweydecima0000fark). > [!abstract] > The Learn Dewey Decimal Classification (edition 23) international edition follows the style and format of earlier editions, with new and revised exercises that incorporate the changes in DDC’s 23rd edition. It covers principles of classifying with DDC, components and organization of the Dewey Decimal Classification, finding numbers in the schedules, building numbers using each of the Tables, and number building by adding from the schedules. --- ## quotes ‘In the print version of DDC, numbers are written in groups of three digits, with a space between each group—e.g., 344.063 635 1. This is done to make remembering and writing numbers easier.’ [[Farkas, Learn Dewey Decimal Classification, 2015|(Farkas 2015, 10)]] ^fe3dc1 ‘Some copy cataloging sources, including cataloging-in-publication, show the segmentation of DDC numbers, to enable shorter numbers to be identified easily. Segmentation is often indicated in DDC numbers by using apostrophes to show where a meaningful number can be ended. For example, 025.4’31 means that 025.431 is the complete number, but 025.4 is also correct (although less specific).’ [[Farkas, Learn Dewey Decimal Classification, 2015|(Farkas 2015, 10)]] ^f51a9c ‘Resources that are used together should be shelved together.’ [[Farkas, Learn Dewey Decimal Classification, 2015|(Farkas 2015, 1)]] ^86bf5f