Stamps may be required.Logical formLearned from10 sentences. A set of stamps may be issued.Logical formLearned from10 sentences. Some persons may receive (food stamps).Logical formLearned from10 sentences. Stamps may pertain-to an issue.Logical formLearned from10 sentences. Stamps can be valid.Logical formLearned from10 sentences. Some sheets can be constituted-of-or-filled-with some stamps.Logical formLearned from10 sentences. Stamps may be issued on an occasion.Logical formLearned from10 sentences. Stamps can be for a country.Logical formLearned from10 sentences. Versions may pertain-to stamps.Logical formLearned from10 sentences. Some series can be constituted-of-or-filled-with stamps.Logical formLearned from10 sentences. A (postage stamp) may undergo an invention.Logical formLearned from10 sentences. An issue can be constituted-of-or-filled-with some stamps.Logical formLearned from10 sentences. A stamp can be constituted-of-or-filled-with excellence.Logical formLearned from10 sentences. A stamp can be on an envelope.Logical formLearned from10 sentences. A value may pertain-to (food stamps).Logical formLearned from10 sentences.