It was an explicit national program to make sure the oral sources in published form should be returned to the areas where they were originally collected.

However, some oral sources has further clarified the situation about Mallagori's origin.

Many of them were taken from the earliest oral sources, and form part of mankind's permanent heritage.

Probably Boccaccio made use both of written and of oral sources.

It should be pointed out that all the examples of folk literature cited in this article are taken from print, rather than oral sources.

As there is not much written information, oral sources have to be quoted:

There are many variants of this tale, both recorded from oral sources and published.

The style of the language suggests that it was written down, as opposed to being recorded from an oral sources.

He also collected material from literary works and oral sources.

Each author has used both written and oral sources to tell the story of the tribes living within the boundaries of Utah.