Invalid ISBN and RDA

Questions:
If I have an invalid ISBN on my resource, do I qualify it with (invalid) e.g. 020 !z 1742084343 (invalid)? Is the MARC coding $z (Cancelled/invalid ISBN) enough to indicate an invalid ISBN? RDA 2.19.1.5

Answer:
The  correct MARC subfield coding should always be used, and is all that is required to satisfy the RDA requirement to indicate that the ISBN is invalid.  However, some areas are in the practice of also including a qualifier, and it is ok for this practice to continue if considered useful.
(From: NLA RDA FAQ)

This page lists some useful RDA resources:

1. ALCTS regularly offer 1-2 hour information webinars about RDA.  Some of the older presentations are freely available on their website http://www.ala.org/alcts/confevents/upcoming/webinar/cat.  The recordings require Windows Media software and a Codec "Patch", which can be downloaded for free from http://www.gotomeeting.com/code
2. See the ACOC RDA website to keep up to date on developments
3. Information on implementation in the US is available on the LC RDA webpage and some handy record examples
4. Questions and Answers from Stanford University http://lib.stanford.edu/metadata-department/stanford-rda-questions-and-answers. It has not been updated recently, but it does still contain useful information
5. PCC guidelines and standards http://www.loc.gov/aba/pcc/rda/PCC%20RDA%20guidelines/Post-RDA-Implementation-Guidelines.html
6. RDA Cafe http://www.facebook.com/#!/groups/RDACafe/?fref=ts|http://www.facebook.com/#!/groups/RDACafe/?fref=ts
7. Introducing RDA : a guide to the basics / Chris Oliver (YYq 2011-133)
8. Practical cataloguing : AACR, RDA and MARC21 / Anne Welsh and Sue Batley (YY 2012-3786)
9. The RDA primer : a guide for the occasional cataloger / Amy Hart (YY 2011-1321)
10. Describing electronic, digital, and other media using AACR2 and RDA : a how-to-do-it manual and CD-ROM for librarians / Mary Beth Weber, Fay Angela Austin (Sq 020 HOW no. 168)