@article{Cai:1996b,
	key = "Cai 1996b",
	author = "T. Cai",
	title = "On $k$-self-numbers and universal generated numbers",
	journal = FQ,
	volume = 34,
	year = "{\noopsort{1996b}}1996",
	pages = "144-146",
	comment = "checked"}

@article{Patel:1990,
	key = "Patel 1990",
	author = "R. B. Patel",
	title = "The first non-trivial self-twin in an even base $k$",
	journal = IJPAM,
	volume = 21,
	year = 1990,
	pages = "320-325"}

@article{Kaprekar:1956,
	key = "Kaprekar 1956",
	author = "D. R. Kaprekar",
	title = "Self-numbers",
	journal = SM,
	volume = 22,
	year = 1956,
	pages = "80-81"}

@article{Gardner:1975a,
	key = "Gardner 1975a",
	author = "M. Gardner",
	title = "From rubber ropes to rolling cubes, a miscellany of refreshing
problems",
	journal = SA,
	volume = 232,
	number = 3,
	month = "March",
	year = "{\noopsort{1975a}}1975",
	pages = "112-116"}

@article{Gardner:1975b,
	key = "Gardner 1975b",
	author = "M. Gardner",
	title = "Six sensational discoveries that somehow or another have
escaped public attention",
	journal = SA,
	volume = 232,
	number = 4,
	month = "April",
	year = "{\noopsort{1975b}}1975",
	pages = "126-133"}

@article{Patel:1991a,
	key = "Patel 1991a",
	author = "R. B. Patel",
	title = "A note on some particular forms of a self-number",
	journal = BCMS,
	volume = 83,
	year = "{\noopsort{1991a}}1991",
	pages = "325-329"}

@article{Patel:1991b,
	key = "Patel 1991b",
	author = "R. B. Patel",
	title = "Some tests for $k$-self-numbers",
	journal = MSTUD,
	volume = 56,
	year = "{\noopsort{1991b}}1991",
	pages = "206-210"}

@article{Troi&Zannier:1995,
	key = "Troi and Zannier 1995",
	author = "G. Troi and U. Zannier",
	title = "Note on the density constant in the distribution of self-numbers",
	journal = BUMI,
	volume = "9-A",
	year = 1995,
	pages = "143-148"}

@article{Ruzsa:1991,
	key = "Ruzsa 1991",
	author = "I. Z. Ruzsa",
	title = "The density of the set of sums",
	journal = AA,
	volume = 58,
	year = 1991,
	pages = "169-172",
	comment = "checked"}

@article{Zannier:1982,
	key = "Zannier 1982",
	author = "U. Zannier",
	title = "On the distribution of self-numbers",
	journal = PAMS,
	volume = 85,
	year = 1982,
	pages = "10-14",
	comment = "checked"}

@article{Recaman:1973,
	key = "{Recam\'an} 1973",
	author = "B. {Recam\'an}",
	title = "Elementary Problem {E 2408}",
	journal = AMM,
	volume = 80,
	year = 1973,
	pages = 434,
	note = "Solution by D. W. Bange, {\bf 81} (1974), 407",
	comment = "checked"}

@article{Goormaghtigh:1949,
	key = "Goormaghtigh 1949",
	author = "R. Goormaghtigh",
	title = "A bit of numerology",
	journal = SM,
	volume = 15,
	year = 1949,
	pages = "91"}

@article{Joshi:1971,
	key = "Joshi 1971",
	author = "V. S. Joshi",
	title = "A note on self-numbers",
	journal = MSTUD,
	volume = 39,
	year = 1971,
	pages = "327-328"}

@article{Vaidya:1969,
	key = "Vaidya 1969",
	author = "A. M. Vaidya",
	title = "On {Kaprekar's} tests for self numbers",
	journal = MSTUD,
	volume = 37,
	year = 1969,
	pages = "212-214"}

@article{RaoA:1966,
	key = "A. Rao 1966",
	author = "A. N. Rao",
	title = "On a technique for obtaining numbers with
a multiplicity of generators",
	journal = MSTUD,
	volume = 34,
	year = 1966,
	pages = "79-84"}

@article{Makowski:1966,
	key = "Makowski 1966",
	author = "A. Makowski",
	title = "On {Kaprekar's} ``junction numbers''",
	journal = MSTUD,
	volume = 34,
	year = 1966,
	pages = 77}

@article{Laporta&Laserra:1993,
	key = "Laporta and Laserra 1993",
	author = "M. B. S. Laporta and E. Laserra",
	title = "La distribuzione dei self-numbers nelle progressioni aritmetiche",
	journal = RM,
	volume = 42,
	year = 1993,
	pages = "307-313"}