Picture 11 is from Mathisons Studio in Texaman, Nebraska

Photo 12 has no markings.

Photo 13 is by O. D. Welch in Glenwood, Iowa                                        Photo 15 is by Flanders Photography in Glenwood, Iowa

                        Photo 15 is by Newberg in Glenwood, Iowa.  I believe this picture shows from left to right: Clarence Eugene Lincoln, George Washington Lincoln, Thomas Burton Lincoln, Matilda Jane Chappelear Lincoln (standing), and Bessie Lincoln.  Photo was taken around 1890.