To the best of my knowledge, the Altman handling of the Double Undercut Palm was first published on pages 72 and 73 of Marlo's Magazine #4 in 1981. I learned the move from Frank Thompson who taught it to me in New York City in February of 1966.
During my first trip to London in July of 1964 I met Jack Avis who taught me two different handlings he devised of a Double Undercut Palm. The handling with the card(s) being palmed into the right hand was published in his book Vis a Vis on pages 32 and 33 which you published in 1998. If my memory serves me, his other technique which is virtually the same as Altman's was published in an issue of the New Pentagram.