the United States. The most common type of taco in the US is the hard-shell, U-shaped version, first described in a cookbook in 1949. This type of taco is typically served as a crisp-fried corn tortilla filled with seasoned ground beef, cheese, lettuce, and sometimes tomato, onion, salsa, sour cream, and avocado or guacamole. Such tacos are sold by restaurants and by fast food chains, while kits are readily available in most supermarkets. Hard shell tacos are sometimes known as tacos dorados ("golden tacos") in Spanish, a name that they share with taquitos. Various sources credit different individuals with the invention of the hard-shell taco, but some form of the dish likely predates all of them. Beginning from the early part of the twentieth century, various types of tacos became popular in the country, especially in Texas and California but also elsewhere. By the late 1930s, companies like Ashley Mexican Food and Absolute Mexican Foods were selling appliances and ingredients for cooking hard shell tacos, and the first patents for hard-shell taco cooking appliances were filed in the 1940s. In the mid-1950s, Glen Bell opened Taco Tia, and began selling a simplified version of the tacos being sold by Mexican restaurants in San Bernardino, particularly the tacos dorados being sold at the Mitla Cafe, owned by Lucia and Salvador Rodriguez across the street from another of Bell's restaurants. Over the next few years, Bell owned and operated a number of restaurants in southern California including four called El Taco. The tacos sold at Bell's restaurants were many Anglo Americans' first introduction to Mexican food. Bell sold the El Tacos to his partner and built the first Taco Bell in Downey in 1962. Kermit Becky, a former Los Angeles police officer, bought the first Taco Bell franchise from Glen Bell in 1964, and located it in Torrance. The company grew rapidly, and by 1967, the 100th restaurant opened at 400 South Brookhurst in Anaheim. In 1968, its first franchise location east of the Mississippi River opened in Springfield, Ohio. Soft-shell tacos Traditionally, soft-shelled tacos referred to corn tortillas that were cooked to a softer state than a hard taco – usually by grilling or steaming. More recently, the term has come to include flour-tortilla-based tacos mostly from large manufacturers and restaurant chains. In this context, soft tacos are tacos made with wheat flour tortillas and filled with the same ingredients as