Give credit to Royama (1971)

[Daniel Pritchard]

We need to give credit to Royama (1971) for first putting forward the "Roger family" of equations.

Royama, T. 1971. A comparative study of models for predation and parasitism. Researches on Population Ecology. 13:1–91.

It's probably not a good idea to rename the functions now, but we should update relevant help pages.

Thanks to Björn Rall for the suggestion.

[Daniel Pritchard]

As an aside, the introduction paragraph from Royama (1971) communicates a great sentiment, relevant to FRAIR:

Elton (1935), in his review of the works of the great biomathematician, the late Alfred J. Lotka, wrote:

"When Lotka published his first notes on this subject in 1920, animal ecology had entered on a new phase, though we are probably only now beginning to see the importance of it." However, "like most mathematicians, he takes the hopeful biologist to the edge of a pond, points out that a good swim will help his work, and then pushes him in and leaves him to drown."