The Handbook of Texas is quite a remarkable document, and the fact that it appears as it does online is a testament to how seriously Texans take their history.

I think you'll find that each author is listed in the item they wrote, and it might be possible to contact them. (I've met a few of them at conferences here--they do like to talk about history!) Why not try writing to the author of the pieces you have questions about? If you need me to help track them down, just PM the names and I'll ask around or look them up. I work for a fellow who has been involved with that group for about 25 years.

SRS