Abstract homotopy and simple homotopy theory. - Klaus Heiner Kamps; Timothy Porter 001 (World Scientific, 1997)

A Homotopy 2-Groupoid of a Hausdorff Space. - Keith A. Hardie; Klaus Heiner Kamps; R. W. Kieboom (Appl. Categorical Struct., 2000)

A Homotopy Bigroupoid of a Topological Space. - Keith A. Hardie; Klaus Heiner Kamps; R. W. Kieboom (Appl. Categorical Struct., 2001)

Triple Brackets and Lax Morphism Categories. - Keith A. Hardie; Klaus Heiner Kamps; Howard J. Marcum; Nobuyuki Oda (Appl. Categorical Struct., 2004)

A 2-groupoid Characterisation of the Cubical Homotopy Pushout. - Keith A. Hardie; Klaus Heiner Kamps; Peter J. Witbooi (Appl. Categorical Struct., 2004)

A Coherent Homotopy Category of 2-track Commutative Cubes. - Keith A. Hardie; Klaus Heiner Kamps; Peter J. Witbooi (Appl. Categorical Struct., 2011)