Because writing a literature review is a task with specific standard requirements that are different from those of other academic writing assignments, students may benefit from referring to literature review how-to materials that describe the various components of reviews and how to execute them well. One may find a literature review how-to through consulting the instructor of the course, the help desk at the university library, or online academic resources. However, no matter which literature review how-to the student finds, it is likely to describe four review elements: introduction, summary of the work, analysis of the work, and conclusion. . .
Don Ihde called the hypothesis being 'hyped' and referred to clear evidence about the use of optical tools by, ., Albrecht Dürer and Leonardo da Vinci and others. As well the 1929 Encyclopædia Britannica  contains an extensive article on the camera obscura and cites Leon Battista Alberti as the first documented user of the device as early as 1437.  Ihde states abundant evidence for widespread use of various technical devices at least in the Renaissance and . in Early Netherlandish painting .  Jan van Eyck 's 1434 painting Arnolfini Portrait shows a convex mirror in the centre of the painting. Van Eyck also left his signature above this mirror,  showing the importance of the tool. The painting includes a crown glass window in the upper left side, a rather expensive luxury at the time. Van Eyck was rather fascinated by glass and its qualities, which was as well of high symbolic importance for his contemporaries.  Early optical instruments were comparatively expensive in the Medieval age and the Renaissance.