r - Maptype=toner produces maps in color, not black and white - Stack Overflow
GitHub - Citytracking/toner: "Toner" is the name of the high contrast, black-and-white map tiles, and Mapnik stylesheets, used for the Dotspotting project.
Dotspotting's Toner Cartography available for download | Stamen
Stamen Designs OSM Tiles | TrueNorth Geospatial
Map of Baltimore | Matthew Petroff
maps.stamen.com
Toner Reservoir, CO map by US Forest Service - Topo - Avenza Maps
Chapter 2 Mapping with R | Tutorial: Dynamic data visualization with R
Toner Reservoir, CO map by US Forest Service - Topo - Avenza Maps
San Diego City Streets Map Print Wall Art – GeoJango Maps
Long live Toner! | MapTiler
Getting started Stamen maps with ggmap | R-bloggers