「ロベルタ」は、1958年に生まれたボブさんの娘の名前を冠したフォント。
以下、Robert Trogman のブログより抜粋。

There are times when I have stumbled on to sign lettering that I have made fonts from. From a picture in a Belgium magazine I built the font family called Roberta (named for my daughter). I did some promotion with the font using some Spanish phrases. Mexican food Company started using Roberta for their logo as well as the city of Carson adopted the font for their street signs. As yet, no computer font has been made, Dan X. Solo has promised to digitize it for Dover Publications.

Origin of Roberta font - Dr. Type's Blog

Tchaikovsky – Swan Lake, 1973
Font: Roberta II Initials

Tyrannosaurus Rex – Unicorn, 1969
Photographed by Peter Sanders, Designed by Tom Wilkes.
Font: Roberta Fancy

Deep Purple – Shades Of Deep Purple, 1968
Similar Font: Roberta III Initials

update:
January 21, 2020
March 5, 2019