Cover and stamps from Mongolia

Received a letter with stamps from Mongolia:




A very nice envelope and stamps. The stamp on the left is issued in year 2007, for Year of the Pig.
The one in the middle is issued in 2000 (1 July). Aspects of Buddha. T 577 and similar vert designs. Multicoloured. P 12. It is in blocks of 10:
2847 550t. Yamantaka
2848 550t. Mahakala
2849 550t. Inscr “Esura”
2850 550t. Begze
2851 550t. Shridevi
2852 550t. Vajrapani
2853 550t. Kubera
2854 550t. Siti Mahakala
2855 550t. Yama
2856 550t. Inscr “Sritzaturtuka”
The one shown above in the middle is the 10th stamp of the mentioned block, with inscription "Sritzaturtuka". I did some search in the web but couldn't find much details of this issue.

For the stamp on the right most I also couldn't locate much details. If anyone can provide any details of the above nice stamps, do feel free to leave your comments. Thanks.