Titus Brandsma/Arnoldus Wijtenburg 1928 Book introduction
1939 Preface
1928 Preface
1934 Foreword
1935 Preface
1926 Foreword
1938 Foreword (Frisian)
1940 Foreword (Frisian)
1939 Preface
1926 Book introduction
1918 Book introduction
1927 Foreword