Even the historians like Dr. Amalendu De , an expert in Islamic History, could not find any publisher to publish his research materials on "illegal migration and Undeclaed refugees'. Similarly, Prafulla Chakraborty, well for his books on European History, could not find a publisher for seminal work " The Marginal Man." The most striking aspects of this source book published in 1990 that it has very brief bibliography - simply because there is hardly any work on this subject.In last decade there had been some work on the issue of migration and refugees due to international funding on this subject. But still the researchers are very careful not to cross the sacred line what is known as 'secularism'.
Chandan Nandy, the author of one of the few extensibly researched treatise on the subject. States :
" I had to approach the field research with extreme caution lest I ended up , "taking sides", especially because the pernicious debate between the left, centre, and right of the Indian political spectrum invariably castes researchers as either "communal" or "secular'.
A detailed study of transborder migration from Bangladesh to West Bengal by Ranabir Samaddar provides human stories, theories , with some useful data but very careful not put any attention on the communal nature of Bangladesh. Though he put a subsection " the vanishing Hindus of Bangladesh".
Enough literature of riots of 1990 and 1992 , the rapes of hundreds Bhola women were easily available but you would be islated if you would drag them to show the issue of Islamic violence. Even Samadder was much annoyed when a BSF jawan asked him to read "Lajjya."
In a paper Published from Indian Statistical Institute wrote in conclusion that:
"Migration from Bangladesh to West Bengal has been a continuous process since 1947. The reasons are historical, political, social, cultural, economic, geographical, and environmental."
This can be note that the list contains all the factors except the religious or communal one.