Digital Theological Library: The mission of the DTL is to support the library resource needs for scholars and students of religion, providing "free.access for all persons everywhere". Although the DTL is non-confessional, the DTL board affirms several core values. On the subject of "Dietrich Bonhoeffer", for example, DTL offers about 100 free EBOOKS or dissertations, and over 1000 open access journal articles (English language).
Digital Commons is an open access digital repository designed to collect, store, index, and provide access to the scholarly and creative output of various University faculty, students, staff, (including Luther Seminary's Digital Commons). Try searching this vast, open network by your key terms. (You'll find, for example, Luther Seminary Professor Gary Simpson's article, Twentieth-century Profile: Dietrich Bonhoeffer; and Prof. Andrew Root's Reexamining Relational Youth Ministry: Implications from the Theology of Bonhoeffer)
Christian History Magazine (issue 32) offers a free full-color overview of "Dietrich Bonhoeffer: Theologian in Nazi Germany"--a timeline of his life, his friends, his stance and martyrdom against the Nazis, and select quotations. Free PDF download available.
Dietrich Bonhoeffer Institute: The Dietrich Bonhoeffer Institute (DBI) is a Christian intellectual organization which hosts discussions on political issues among clergy and other institution leaders. Its leadership and views tend to support left-of-center political goals, especially concerning gun control and abortion. The organization is named after a German Lutheran pastor who was executed in Nazi Germany for helping Jews escape and coordinating with anti-Nazi movements.
Dietrich Bonhoeffer Quotes: "Top 25 Quotes" from A-Z Quotes from many categories, including "Christ", "community," "discipleship," "grace," suffering'" etc.
100 More Bonhoeffer Quotes from thefamouspeople.com. Note: quotation sources are not provided and therefore some may be questionable.
"Bonhoeffer", the movie by Martin Doblmeier and Vision Video --1.5 hour film on YouTube; interview with film maker, Doblmeier