Roberts, W. D. (1971). Strachan of Costa Rica: Missionary insights and strategies. Eerdmans.
Lua i Stíl Chicago (17ú heag.)Roberts, W. Dayton. Strachan of Costa Rica: Missionary Insights and Strategies. Eerdmans, 1971.
Lua MLA (9ú heag.)Roberts, W. Dayton. Strachan of Costa Rica: Missionary Insights and Strategies. Eerdmans, 1971.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.