Definition of "Malay" in "The Early Malay Doctors"?

Suggestion by Dr Mohamed Tahir, Singapore (29 March 2011):

"With regard to "Malay", I think you should use the definition of Malay as in the Malaysian constitution - article 160. Though this was enacted later than the early doctors it can still be applied for your purpose. The article defines a Malay as a citizen who professes to be a Muslim, habitually speaks the Malay language, adheres to Malay customs and is domiciled in Malaya or Singapore.

If you just use ethnic or "pure" Malays, then you won't have much of a list."