Fratelli Spada stories - Easter Eggs
Unsure why the artist made a large billboard that points to a car with the text: Your old car.
A book title: Confucio Massim(o). Probably something to do with Massimo Liorni.
On the cover of Mandrake #153 from 1970 one can read BossyK LiornyK. - Seems like U.Sam was not quite satisfied with his boss when he made this cover.
The use of the letters EF is some stories is likly a hidden signature made by Ennio Ferri.
It can be seen in the "Magia bianca" story where Mandrake is reading a newspaper with a EF logo on the first page. In this story the same letters also appears on the back page, but now as EF. RI. This newspaper is used in the stories "Ore zero ... camera a gas" and "Narda allo sbaraglio". The last one includes the letters GF, which probably refers to the co-artist - his brother Germano Ferri.
The initials D.M. showing on a license plate in the story "Il giustiziere"
In the story "La clinica del dottor Mefix" there is a panel showing the spine of some books in a bookshelf - SAM + LIO + RNI. The name SAM is likely the hidden signature of the artist, Umberto Sammarini. And the LIO + RNI refering to Massimo Liorni, the head of Fratelli Spada.
In the "Il congresso dei maghi" story 'SAM is used on a bottle and as a name for a bar.