This $3.00 endgame book is better than Fundamental Chess ENdings

https://lichess.org/study/TgO5fzP9

I found a link which explains "Bird's Color Rule", which is a system for deciding where to push your pawns if you are the  attacking player in the K+ NP+RP vs K +RP ( NP and RP adjacent and RP's opposing each other) ending.  It did not mention what Bird had to do with it or who coined the term, but it tells you how to find the winning method depending on what colors the kings and pawns are on.

Paul Keres examines  endings of a similar make-up  of Kings and pawns starting on diagram 88 in his book  "Practical Chess Endings". The original classic from 1974 was in descriptive notation, but there is a 2nd revised edition in algebraic notation  published by Batsford in 2018.  I just ordered the book on the basis of excerpts I read.  Keres seems to explain things clearly and delves into different winning and drawing possibilities depending on the nuances of the specific positions.

I first saw this position about 15 years ago in GM-RAM (Ziyatdinov) -- worked out the color rule myself (thank you, Ziyatdinov for no notes!) -- The rule comes in handy in other scenarios. Did not know it was called Bird's Color Rule until de la Villa's 100 Endgames You must Know. I'd never seen anything published about the color rule, much less that it had a name, and a google search seems to turn up nothing, but it did bring me here.