Lagrange's four-square theorem - Wikiwand

Table 1 from Extended Lagrange's four-square theorem

PDF) Two refinements of Lagrange's four-square theorem

Sums of four squares — AnhThu Nguyen

What is lagrange theorem? - Quora

5. * In the following sequence of problems, we will

Lagrange's four-square theorem

GitHub - HechenHu/Four-Square_Representation: Using Rabin and Shallit's Algorithm to compute the four-square representation of a natural number as stated in Lagrange's Four-square Theorem.

number theory - The Four Square Theorem and Integral Apollonian Circle Packings, is there any connection? - Mathematics Stack Exchange

Lagrange's Four-Square Theorem by Julian TSE

PDF) Sums of four squares and Waring's Problem