Xinyao, Shen et Kefeng, Ying, Some Results on Unstable Polynomial Algebras over the Steenrod Algebra, Acta Mathematica Sinica, New Series Chinese Journal of Mathematics, 7(3), 1991, pp. 241-246
In this paper we give a condition under which an unstable polynomial Ap-algebra can be obtained from the modular polynomial algebra. From this we car deduce both the Aguades theorem and Clark's theorem