Sentence case is the way sentences are capitalized in English, with the first word in the sentence capitalized, along with all proper nouns:
There are many books in the House of Learning at Thompson Rivers University.
In APA references, the titles and subtitles of books, articles and other works are given in sentence case:
Enhancing the evaluation of nursing care effectiveness.
Active gaming in Dutch adolescents: A descriptive study.
Status of the western harvest mouse in British Columbia.
The names of journals, magazines and newspapers, on the other hand, are given in title case, with all of the major word capitalized:
The International Journal of Behavioral Nutrition and Physical Activity