Now showing items 40-46 of 46

    • Ten Mathematical Equations 1 

      Unknown author (1971)
      Two stamps from The Ten Mathematical Equations that Changed the Face of the Earth series. Issued by Nicaragua on May 15, 1971.
    • Ten Mathematical Equations 2 

      Unknown author (1971)
      Two stamps from The Ten Mathematical Equations that Changed the Face of the Earth series. Issued by Nicaragua on May 15, 1971.
    • Ten Mathematical Equations 3 

      Unknown author (1971)
      Two stamps from The Ten Mathematical Equations that Changed the Face of the Earth series. Issued by Nicaragua on May 15, 1971.
    • Ten Mathematical Equations 4 

      Unknown author (1971)
      Two stamps from The Ten Mathematical Equations that Changed the Face of the Earth series. Issued by Nicaragua on May 15, 1971.
    • Ten Mathematical Equations 5 

      Unknown author (1971)
      Two stamps from The Ten Mathematical Equations that Changed the Face of the Earth series. Issued by Nicaragua on May 15, 1971.
    • Ten Mathematical Equations 6 

      Unknown author (1971)
      First-day cover with five stamps from The Ten Mathematical Equations that Changed the Face of the Earth series. Issued by Nicaragua on May 15, 1971.
    • Ten Mathematical Equations 7 

      Unknown author (1971)
      First-day cover with five stamps from The Ten Mathematical Equations that Changed the Face of the Earth series. Issued by Nicaragua on May 15, 1971.