On Finite Models of the Lambek Calculus. - Maciej Farulewski (Stud Logica, 2005)

Finite embeddability property for residuated groupoids. - Maciej Farulewski (Reports Math. Log., 2008)

Nonassociative Lambek Calculus with Additives and Context-Free Languages. - Wojciech Buszkowski; Maciej Farulewski (Languages: From Formal to Natural, 2009)