Bulgaria – Turkey: 1910 (29 March). Stampless cover from Sophia to Constantinople with circular ‘T’ postage due cachet franked on arrival with ‘T’ handstamped 1pi postage stamp of 1909 and 1pi postage due of 1908 stamps tied by Pera and Stamboul 12 April arrival cds’s. Scarce usage of mix reign stamps. Isfila 269, 279
