The aforementioned announcement, is contained in the "DFIM Circular Letter No. 20" and the "DOS Circular Letter No. 22", themselves based on the earlier, but just released, "Govt. Notification No. 05.00.0000.173.08.005.11-325/1(150) dated 03-11-2011" of the Ministry of Public Administration, Government of the People's Republic of Bangladesh.
One oddity in the aforementioned announcement is the date stated for the Buddha Purnima (Baishakhi Purnima) public holiday which is listed a month later than one would have expected (and which is listed by the governments of India and Sri Lanka).
Another, albeit minor, oddity is the July 6 date announced for the Lailatul Barat public holiday in 2012 in Bangladesh.
Links and References
Below are links to the news stories referred to in the above "Bangladesh 2012 Public Holidays List Approved" news story, as well as links to subsequents news stories which refer to the present news story.