Today almost all Interpostal Seals collectors use the system of cataloguing and identification numbers established by Ernst Kehr set in his “Kehr Catalogue of Interpostals” published in 1984 (cover page shown below to the leftt). An earlier issue of this catalogue was published in the 1960’s (cover page shown). Kehr was a prominent philatelist whose father lived in Egypt, travelled within the country and, presumably, arose his interest in this material. A synopsis of Kehr’s works and publications appeared in volume 14 of the “Catholic Who’s Who Book of 1945”, shown here, next to his picture. Kehr died in 1986. All classification of seals on this site use the “Kehr Type” and Kehr “Catalogue Number” .