As a historian del Burgo is praised for sound referential basis; the critics usually point to his Carlist bias. He is particularly criticized for an attempt to recalculate the number of victims of the Rightist terror in Navarre; other historians support 4 times higher figures. This controversy coincides with the fact that del Burgo was personally accused of a war crime, the charge that left him very embittered and which he always denied; it is also disqualified by some historians. As an amateur he has never assumed academic duties, though he became member-correspondent of ; for his bibliographical work del Burgo received the National Literary Prize in 1967.