Technical Documentation: Journal Metrics
General documentation regarding the Serial title Metadata API is here.
Here is an example request, retrieving only the SJR and SNIP, for the "European Journal of Marketing" (by ISSN):
http://api.elsevier.com/content/serial/title?issn=0309-0566&field=SJR,SNIP&view=STANDARD
It returns the following XML results:
<serial-metadata-response xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:ns2="http://webservices.elsevier.com/schemas/metadata/abstracts/types/v10" xmlns:prism="http://prismstandard.org/namespaces/basic/2.0/">
<link href="http://api.elsevier.com/content/serial/title?&issn=0309-0566&start=0&count=25&view=STANDARD&field=SJR,SNIP" ref="self" type="text/xml"/>
<entry>
<SNIPList>
<SNIP year="2006">0.461</SNIP>
<SNIP year="2007">0.838</SNIP>
<SNIP year="2008">1.185</SNIP>
<SNIP year="2009">1.727</SNIP>
<SNIP year="2010">1.515</SNIP>
<SNIP year="2011">1.689</SNIP>
</SNIPList>
<SJRList>
<SJR year="1999">0.000</SJR>
<SJR year="2000">0.000</SJR>
<SJR year="2001">0.000</SJR>
<SJR year="2002">0.000</SJR>
<SJR year="2003">0.000</SJR>
<SJR year="2004">0.000</SJR>
<SJR year="2005">0.000</SJR>
<SJR year="2006">0.034</SJR>
<SJR year="2007">0.034</SJR>
<SJR year="2008">0.036</SJR>
<SJR year="2009">0.035</SJR>
<SJR year="2010">0.033</SJR>
<SJR year="2011">0.036</SJR>
</SJRList>
<prism:url>http://api.elsevier.com/content/serial/title/issn/0309-0566</prism:url>
</entry>
</serial-metadata-response>
Also, you'll need to put the following text wherever you display the values...
...For SNIP:
Source Normalized Impact per Paper (SNIP) measures contextual citation impact by weighting citations based on the total number of citations in a subject field. [Powered by Scopus]
...For SJR:
SCImago Journal Rank (SJR) is a measure of scientific influence of scholarly journals that accounts for both the number of citations received by a journal and the importance or prestige of the journals where such citations come from. [Powered by Scopus]
Where [Powered by Scopus] is this graphic: 
In addition, we highly recommend links to http://www.journalmetrics.com/sjr.php and http://www.journalmetrics.com/snip.php to provide more explanation regarding the values.
