Dextroamphetamine, along with other sympathomimetics, was eventually classified as Schedule II, the most restrictive category possible for a drug with a government-sanctioned, recognized medical use.

Internationally, the drug is in Schedule IV of the Single Convention on Narcotic Drugs, that treaty's most restrictive category.

In the United States, it is in Schedule I of the Controlled Substances Act, the most restrictive category, which allows no medical use.

That has let it qualify for a less restrictive category of controlled substances, he said, opening it to office use by trained physicians.

The restrictive categories that disproportionately benefit urban districts include aid for summer school, bilingual education, homeless students, incarcerated youth and magnet schools.

Based on such ideas, several restrictive categories of interest have been identified.

In 1996, under the same law, the first six All-American Roads were designated for their historic value, along with 14 National Scenic Byways, a less restrictive category.

In addition, the administration proposed moving Latvia from the Tier 3 group of nations to the least restrictive category, Tier 1.

Company payment for job-related courses, a far more restrictive category, is still tax free.

It is also not known what may be missing from the material, either because it is in a more restrictive category of classification or for some other reason.