THEORIE DES TRANSITIONS DE PHASE DANS LES FERROELECTRIQUES, AVEC FORMATION D'UNE SURSTRUCTURE NON MULTIPLE DE LA PERIODE INITIALELEVANYUK AP; SANNIKOV DG.1976; FIZ. TVERD. TELA; S.S.S.R.; DA. 1976; VOL. 18; NO 2; PP. 423-428; BIBL. 9 REF.Article

RAMAN SPECTRA OF (NH₄)₂BEF₄.WADA M; SAWADA A; ISHIBASHI Y et al.1977; J. PHYS. SOC. JAP.; JAP.; DA. 1977; VOL. 43; NO 3; PP. 950-953; BIBL. 6 REF.Article

F₂^- MOLECULAR IONS IN GAMMA -IRRADIATED (NH₄)₂ BEF₄ SINGLE CRYSTALMATSUKI K; OHNO K; SOHMA J et al.1979; J. PHYS. SOC. JPN.; ISSN 0031-9015; JPN; DA. 1979; VOL. 47; NO 6; PP. 1897-1902; BIBL. 17 REF.Article

A MODEL OF AN INCOMMENSURATE-COMMENSURATE PHASE TRANSITIONDVORAK V; ISHIBASHI Y.1978; J. PHYS. SOC. JAP.; JPN; DA. 1978; VOL. 45; NO 3; PP. 775-780; BIBL. 14 REF.Article

EFFECT OF RADIATION DAMAGE ON FERROELECTRIC PHASE TRANSITION IN (NH₄)₂BEF₄OHNO K; MATSUKI K; SOHMA J et al.1979; MEM. FAC. ENGNG, HOKKAIDO UNIV.; JPN; DA. 1979; VOL. 15; NO 1; PP. 75-81; BIBL. 13 REF.Article

ELASTIC COMPLIANCES AND ULTRASONIC ATTENUATION IN (NH₄)₂BEF₄ IN THE TEMPERATURE RANGE FROM 170 TO 190 KSORGE G; ALMEIDA A.1979; PHYS. STATUS SOLIDI, A; DDR; DA. 1979; VOL. 51; NO 2; PP. K181-K184; BIBL. 20 REF.Article

ELECTRON SPIN RESONANCE STUDY OF HYDROGEN ATOMS TRAPPED IN AMMONIUM FLUOROBERYLLATEMATSUKI K; OHNO K; SOHMA J et al.1978; JAP. J. APPL. PHYS.; JPN; DA. 1978; VOL. 17; NO 10; PP. 1707-1712; BIBL. 29 REF.Article

SURFACE LAYER EFFECTS ON THE DIELECTRIC BEHAVIOUR OF POLYCRYSTALLINE AMMONIUM TETRA FLUORBERYLLATE.SAMBASIVA RAO K; BHANUMATHI A.1978; J. PHYS. SOC. JAP.; JAP.; DA. 1978; VOL. 44; NO 2; PP. 505-508; BIBL. 12 REF.Article

ETUDES DE MANDELSTAM-BRILLOUIN ET ULTRASONORES DES TRANSITIONS DE PHASE DANS LE CRISTAL (NH₄)₂BEF₄ALEKSANDROV KS; ANISTRATOV AT; KRUPNYJ AI et al.1976; KRISTALLOGRAFIJA; S.S.S.R.; DA. 1976; VOL. 21; NO 3; PP. 534-537; BIBL. 19 REF.Article

PROPRIETES THERMIQUES DES CRISTAUX DE FLUOROBERYLLATE DE NH₄ DANS UN GRAND INTERVALLE DE TSTRUKOV BA; SKOMOROKHOVA TL; KOPTSIK VA et al.1973; KRISTALLOGRAFIJA; S.S.S.R.; DA. 1973; VOL. 18; NO 1; PP. 143-146; BIBL. 13 REF.Serial Issue

CHANGES OPTICAL PROPERTIES AT AN INCOMMENSURATE-COMMENSURATE PHASE TRANSITION IN (NH₄)₂BEF₄ CRYSTALSKONAK C.1979; PHYS. STATUS SOLIDI, A; DDR; DA. 1979; VOL. 54; NO 1; PP. 99-104; ABS. GER; BIBL. 20 REF.Article

ASPECTS OF SYMMETRY IN THE PROBLEM OF PHASE TRANSITIONS IN IMPROPER FERROELECTRICS.ZHELUDEV IS.1977; PRAMANA; INDIA; DA. 1977; VOL. 9; NO 4; PP. 385-397; BIBL. 12 REF.Article