I am currently dealing with a big mess in my great great grandmother. Here is an example.
<ref>Source: [[#S1646]] Year: 1920; Census Place: Jonesport, Washington, Maine; Roll: T625_650; Page: 14B; Enumeration District: 175; Image: 612 Page Year: 1920; Census Place: Jonesport, Washington, Maine; Roll: T625_650; Page: 14B; Enumeration District: 175; Image: 612</ref>
which links to this in sources section
* Source: <span id='S1646'>S1646</span> Ancestry.com, 1920 United States Federal Census (Ancestry.com Operations, Inc.) s, Inc. Note: Fourteenth Census of the United States, 1920. (NARA microfilm publication T625, 2076 rolls). Records of the Bureau of the Census, Record Group 29. National Archives, Washington, D.C. For details on the contents of the film numbers, visit the following NARA web page: <a href="
http://www.archives.gov/publications/microfilm-catalogs/census/1920/part-07.html" target="_blank">NARA</a>. Note: Enumeration Districts 819-839 are on roll 323 (Chicago City). TID 0 Footnote Ancestry.com, 1920 United States Federal Census (Ancestry.com Operations, Inc.) ShortFootnote Ancestry.com, 1920 United States Federal Census Bibliography Ancestry.com. 1920 United States Federal Census. Ancestry.com Operations, Inc. Repository: [[#R4]] Year: 1920; Census Place: Jonesport, Washington, Maine; Roll: T625_650; Page: 14B; Enumeration District: 175; Image: 612 Page Year: 1920; Census Place: Jonesport, Washington, Maine; Roll: T625_650; Page: 14B; Enumeration District: 175; Image: 612
All of that boils down to just this little valid info under sources.
* Source:1920 United States Federal Census (Ancestry.com Operations, Inc.) Fourteenth Census of the United States, 1920. Census Place: Jonesport, Washington, Maine; Roll: T625_650; Page: 14B; Enumeration District: 175; Image: 612 Page Year: 1920; Census Place: Jonesport, Washington, Maine; Roll: T625_650; Page: 14B; Enumeration District: 175; Image: 612.
This lets you know where you could find it if you have access to the actual film. It can still be used to cross check if you find something in familysearch at which point it will get replaced.
So, that #S4 may hook to something else in the sources. It was sort of an ancient ref tag. It can probably be deleted. But try to salvage as much info as possible if you can.
(BTW the one link in the whole mess is no longer valid due to changes at that website)