Three Theorems on Phrase Structure Grammars of Type 1 - Peter S. Landweber (Inf. Control., 1963)

Decision Problems of Phrase-Structure Grammars. - Peter S. Landweber (IEEE Trans. Electron. Comput., 1964)

On Fiber Diameters of Continuous Maps. - Peter S. Landweber; Emanuel A. Lazar; Neel Patel (Am. Math. Mon., 2016)