There is clearly a problem with each new generation of books and articles each repeating earlier sources and not using original material.
Mr Paul Graham in the Spring 2007 edition of Air Power Review, writing about RAF NUclear Deterrence in the Cold War fell in to this trap when he included a table Statistics of Contemporary Bombers from another source. A source is cited but there are 10 different sources under that endnote; are we to believe that the ensuing table is Graham's own work?
There is a table with Range quoted in kilometers and speed in knots or mach together with a service ceiling in feet.
The table suggests a B52 as capable of 883k/0.84M and a Bear at 970k/0.79M. Inspection would suggest two error. Converting km to nautical miles gives 477 and 524 with the latter being rather faster than 0.79M would suggest.
The Vulcan Mk 1 is quoted at 0.84M and the Mk 2 at 0.96M. I seem to recall the Mark 1 actually had a higher mach number. As for the ceiling of the Vulcan Mk 2 at 65000ft, this is certainly questionable and not the published in-service figure. The 4000 mile range and 8 hour plus flight time are really Observer's Book of Aircraft stuff.
Much of the rest of the article seems accurate and authoritative but its credibility is thrown in doubt be sheer errors in an inconsequential table.
At least if contemporary primary sources are used, years after the event, an author can claim lapse of memory from his contributors.