I've noticed, scanning old TV Guides and checking against Ed Slonina's online episode guide which is now only available via webarchive.org, that Mr. Slonina's guide has quite a few errors and omissions. A few examples:
- Roddy McDowall's 9th-season guest appearance was claimed to be aired on Nov. 8, 1975 when, in fact, it was on Nov. 1, 1975;
- What did air Nov. 8 was a guest appearance by Helen Reddy, but Mr. Slonina didn't mention this show at all;
- The synopses of Maggie Smith's two ninth-season appearances were switched; that is, what was aired on Oct. 18, 1975 was mistakenly attributed to the Nov. 15, 1975 edition - and vice versa;
- On one of Steve Lawrence's 9th-season guest appearances, one of the songs he sang was "In the Still of the Night" - yet the guide claims he sang "In the Wee Small Hours";
- Vivian Bonnell, a frequent supporting sketch player from c. seasons 2-5, was misidentified as Vivian "Blondell" on a second-season show where Flip Wilson was a guest;
- Jessica Walter (now appearing in Retired at 35) had an "s" added on to her surname where she has none;
- and many cases where you'd be seeing a sketch on Carol Burnett & Friends and unless you were really familiar with the show's history, you couldn't tell where such sketch came from (in one example, it was on the show with Ms. Walter that the sketch about the 1905 Russo-Japanese peace treaty negotiations, with Harvey Korman as a Russian official and Tim Conway as a Japanese delegate, first aired).
These have all wrought havoc with historians, and even played havoc on IMDb where now you have some episodes from the 11th season where a guest from the 9th season is placed where they shouldn't be, and even episodes within the 9th season where some guests have been moved around where they shouldn't be (and I, being a registered IMDb'er, have tried my best to place them in the correct places).