Hi Jennifer,
MLA is a highly intelligent but exceptionally complex style. Over the years I have managed to tame it a little. Here’s how I handled the issue of provenance of electronic media. It works Ok, maybe 98% of the time, and I think is a pretty efficient approach.
Rather than making separate Reference Types for print and electronic media for each of journals, books, reports, etc and so on, I looked in the Reference Types table (Edit… Preferences… Reference types…) and found some fields that I could use to handle the electronic sources across all reference types:
Custom 5: Medium [I set this one in place]
URL: URL [Already there]
Author Address: URL for MLA [I set this one in place since I don’t need the author address]
Access Date: Access Date [Already there]
Name of Database: Name of Database [Already there]
You can then add the fields in the appropriate places in your bibliography templates. No need to do this for the gazillion reference types supplied in Endnote: I just did it for the ones I actually use, e.g., journal article, magazine, book, book section, etc.
And some examples of books and pamphlets:
Whiteside, Thomas C. D. The Problems of Vision in Flight at High Altitude. London: Butterworths, 1957. Print. [A regular book: “Print” is in the Medium field]
Maddox, Ernest E. The Clinical Use of Prisms; and the Decentering of Lenses. 2nd ed. Bristol: John Wright, 1893. Web. Google Books. 14 September 2012. [A facsimile copy on the Web. “Web” is in the Medium field, “Google Books” is in the Name of Database field, and my access date is in the Access Date field.]
Keith-Spiegel, Patricia, Joan Sieber, and Gerald P. Koocher. Responding to Research Wrongdoing: A User-Friendly Guide. 2010. PDF File on Web. 21 July 2012. ‹address›. [A web address is supplied in the URL for MLA field. I had to enter “address” in this post instead of the actual web address since this site would not accept my post otherwise. I use this field rarely if I think the organization name would be anything but entirely straightforward to locate. MLA allows you to do this.]
I retain the URL field for other journal styles that require the actual URL (e.g., Vancouver).
MLA looks so much nicer than the others for not requiring long and messy URLs!
Over the last decade I have noticed more and more styles wanting the provenance of electronic sources. I have got into the habit now of always recording: URL (copy and paste it), the name of the site or database (e.g., J-STAGE, Wiley Online Library), and the date when I accessed it.