no problem that is the strength of wikipedia collaboration you don't have to get it perfect on your own i have changed the tag to indicate that it lacks footnotes rather than refs since you have added the refs it is probably easier to add footnotes as an article is being written rather than after the fact which as you point out would be a lot of work now when i had the refs such as in the case of v speeds i have been able to reference a list like this in the past retroactively but i don't have the refs for this article i think the article is very useful and i hope that it will be retained and expanded over time thanks for starting it