Merkel, K., & Forster, K. W. (2000). Trilogy of stone and time: Klaus Merkel ; with a preface by Kurt W. Forster. Lars Müller Publishers.

Merkel, Klaus, and Kurt W. Forster. Trilogy of Stone and Time: Klaus Merkel ; with a Preface by Kurt W. Forster. [Zürich], Switzerland: Lars Müller Publishers, 2000.

Merkel, Klaus, and Kurt W. Forster. Trilogy of Stone and Time: Klaus Merkel ; with a Preface by Kurt W. Forster. Lars Müller Publishers, 2000.